Isekai Survival Guide

[2095conash]

Man it's been awhile since I've updated this some hasn't it? Sorry about that life has generally gotten in the way quite a bit. Two quick notes before we get into things, first if you saw my edit for my second post saying that one of my sources was highly disputed, please disregard that as I have since talked to a history expert and while he may not be able to prove the video true all himself (as it crosses several fields of expertise) he went a bit into detail about how a lot of the criticism I had been listening to is pretty unfounded, and I found his claims and reasoning to stand up a bit more scrutiny than those criticisms, second the previous post about 'Water Acquisition' has had a 4th point added onto it in post as I came across another method of getting water while researching this post. That out of the way, you've had more water than you know what to do with for nearly half a year now so let's talk about good ways to put it to use shall we?

Water Application

• Hygiene- Hygiene is very important not only to make sure you are pleasant to be around, but also for your health (like preventing yourself from getting or spreading 'Dragon Pox'), and in a world without modern conveniences it's important to fully understand the hygiene situation, and one Isekai that does a good job looking at dealing with Hygiene both with and without magic would be Death March to the Parallel World Rhapsody, here you have an early chapter where the MC has to draw water from a well to have a somewhat public shower using a cloth but later on this isn't an issue as the MC gets access to 'life magic' which allows him to wash and dry not only himself but others with magic. You can find these types of 'lifestyle' magics in various isekai stories, and if it's around then you probably won't have to worry about this a whole lot, but we don't know if/when you'll get access to this if your world has access to it, so let's look at some low-tech solutions! One thing that you'll want for sure though is some soap to keep extra clean, and I at one point came across this isekai where the main character does go into making soap, however after further research I found that 'soap' predates baking soda (which they use for their soap recipe) by a long time, so why don't we try looking at a bit more of a low-tech soap making recipe shall we? This video helps cover ways to make soap, and the research that I've done suggests that you can use ceramic containers instead of metal containers if that's not available to you, and I'll get into making those in a later post, so hopefully you don't get Isekai'd before then!ter in them (like bamboo or banana trees).
  
  One other point of Hygiene though that's probably far less likely to be already developed in a low-tech world however would be good dental Hygiene, given how important our teeth are to eating understanding what goes into making a tooth brush and tooth-paste can go a long way in helping you able to chew your food for years to come, as shown in this video dental hygiene is going to greatly benefit from having either a magic alternative or already been well developed, as getting the sorts of hairs needed for good bristles of a tooth-brush can be very hard and while making a toothpaste shouldn't be too difficult as it's largely just putting together a bunch of abrasive substances to cut away at the gunk on your teeth, modern technology has come a long way in helping us create toothpastes that aren't harmful to the body, don't taste absolutely sickening, and can do a better job than low-tech toothpastes. In regards to flossing however you're not really looking at anything radically different, I've talked with my dentist quite a bit and flossing doesn't really accomplish anything fundamentally different as brushing your teeth, it just gets into the places your tooth brush can't reach, heck in my case I'm missing a few teeth that has created some gaps between my teeth making flossing pointless for those areas as a toothbrush can easily reach into those gaps (though I still need to floss between most of my teeth), so all that you really need to do is apply the same principles as brushing your teeth into those spaces.

• Plumbing- So we've covered how to get yourself soap, a toothbrush, and toothpaste even without human civilization, so since not every isekai will just handwave plumbing as something that is magically created by geniuses like in this example, it'd be a good idea for us to try to find ways to be able to setup toilets and plumbing in general for our possibly low-tech world. One of the best examples to look at for this situation would be the Romans, for them a toilet was basically a seat that you sat on that inside it was a constant stream of water flowing so that the natural flow of water would handle your business, and while they weren't wealthy enough to have them installed in every home, public bathhouses with toilets went a long way to help keep the city cleaner (though I quickly want to mention that I'm disappointed this isekai was of no help with what you need to build a bathhouse or hot spring). Honestly the technology for the toilets aren't that impressive nor was their methods of cleaning the streets as they just made sure that an incline would have water flow naturally, but well this would be a great place to talk about just really look into how their water system worked to better understand all the tricks you can use to transport water across long distances (acquisition of water was already pretty long, and this plays not only into plumbing but also irrigation so let's have it here!). See, while the Romans aren't the only civilization that had a sort of water system, they're the best example to use for this due to the myriad of methods their water system incorporated to overcome challenges, for a bit of a reference guide let's look at this video. Now, I don't know about you, but on my first viewing that whole lead pipe thing that had water going uphill caught my attention, and while we can't guarantee that we'll have lead pipes available (though since we now know that lead poisoning is a very big risk, you would hopefully have safer alternatives available, but more on those in a later post), let's work to understand the basic principle behind it in order to utilize it ourselves, first to demonstrate the basic principle I recommend this video, and to apply it to a much larger scale in structures (and without using using a giant pipette) this video gives a good demonstration as to how to what the Romans did. Pretty simple stuff, using gravity and water/air pressure to subvert gravity huh? Well after you are done getting praised as the greatest water mage this new world has ever seen for your little physics trick, let's go back to the reference guide to explore something else they did. See, going uphill certainly helps but there comes a point where that alone isn't enough and sometimes you'll have to go through some landmass, and to better understand good ways of accomplishing this I think that it'd be good to head over to the Middle East, where they were doing something similar long before the Romans with their Qanats, which you can see explored how to make those here. Now, the aqueducts themselves were also quite fundamental to the Roman's plumbing system ranging from their architecture, the material used, and even the size of them but details on that will be better explored in a later post on architecture as a whole, for our purposes here the only additional information to note about the Roman plumbing system is that once the water was on the aqueducts they relied basically on gravity and inclines to do the rest of the work, so you're going to have to make sure that you get very accurate measurements as to the distance you need to travel to make sure the degree of steepness is correct, and when you want to send some water to homes or farms some pipes diverting some of the water will do you good! Sadly though, I haven't found any information confirming if you could use ceramics or something that's not a metal to use for pipes, so depending on your tech you might have to rely entirely on Qanats.

• Waterwheel- Now, while I can't stress the importance of hygiene enough, let's talk waterwheels some. So, this isekai brings up waterwheels fairly early on, and implementation of many waterwheels becomes one of the focuses for awhile, but while it talks a bit about how they work it doesn't get too in-depth about the construction of them. Which is pretty fair, waterwheels are pretty fairly easy to make all things considered, so long as you're not picky about size or function that is as demonstrated in this (quiet) video. Now, in the before linked isekai they only use waterwheels basically for irrigation which isn't a bad use, but waterwheels can be used for so much more, like electricity however that seems a bit advance for this stage of things, so instead we'll focus a bit on using them for a mill like demonstrated here. Now as mentioned in the video, a big part of grinding flower comes down to just having two stones, one that turns and one that doesn't, and this can be fairly easy to set up with our technology by putting a pole through the waterwheel that connects to a gear that crosses with another gear perpendicularly that then connects to the stone that you spin, but if you're in a world with gears readily available I'm going to have a hard time believing that they don't already have plenty of waterwheels in use as is, so let's take a second and look at how to get the sort of setup that I'm referring to approximately with wood. This video for example serves as a very good reference point, as while it doesn't explain how to make the stuff involved or set it up, it shows a waterwheel setup made entirely from wood that would be able to work in setting up a grindstone for a mill, it then examines the setup from multiple angles helping to give you a full idea as to the setup (for example the importance of making sure that the spacing between the teeth of the wheel work with the boards of the gear so it doesn't jam), though the use of nails and screws may make this exact setup tricky depending on the world you end up in, still the ability to use waterwheels to automate work that would otherwise need to be done by human hands could improve your new home by leaps and bounds!

References:

1. Death March to the Parallel World Rhapsody Web novel, Light Novel, Manga, and Anime. An Isekai where the main character ends up at an incredibly high level, and slowly accumulates a large group of pseudo-daughters while he tries to do what he can to help people. Well recommended for entertainment value.
2. I opened an orphanage in another world, but for some reason no one wants to leave. Web novel, Light Novel, and Manga. An Isekai where the main character was determined to not have skills suitable to save the world, so was instead put in charge of a run-down orphanage where he must use his skills so repair and run the place, and seems to build some type of loli-harem from how far I got. Not recommended for entertainment value.
3. making soap from wood ashes a video demonstrating how to make soap with wood ashes in an easily understood way. Not recommended for entertainment value.
4. Pig Hair Toothbrush, Sand, and Hooves: Teeth Cleaning from Scratch a video exploring the requirements of how to make a toothbrush and toothpaste, including interviews with dentists, making some low-tech versions of both and getting people to try them out. Has some humor and is easy to follow, but is otherwise not recommended for entertainment value.
5. Eighth son, I don’t think so! Web novel, Light novel, and Manga. An Isekai where the main character is incredibly gifted in magic, and after being trained by one of the world's greatest wizards before their death goes on to become an adventurer. Only recommended for entertainment value if you can appreciate a power fantasy in of itself.
6. I was Reincarnated as a Hot Spring in an Alternate World, and I'm Way Too Effective An isekai where the main character is reincarnated as a hotspring and has to use his limited powers to try to become a successful hot spring by leveling up and working with the locals. Not recommended for entertainment value.
7. Roman Water Supply | Strip the City A video that briefly covers the various methods the Romans used to transport water from springs into their cities. Slightly recommended for entertainment value.
8. The Siphon A video that explains and demonstrates how a water syphon uses air-pressure to defy gravity. Recommended for entertainment value.
9. Roman water ran uphill A video that helps briefly show how the Romans used siphons on large scales to move water uphill. Not recommended for entertainment value.
10. Iran Kariz ancient underground water plants A video that shows how Iranian Qanat's work, brief clips about how they're formed, and some talk about how important they are for Iran. Not recommended for entertainment value.
11. Won 4 Billion in a Lottery But I Went to Another World Web novel and Manga. Isekai where the MC won the lottery, moved into a house his dad had, then found a locked room that lead to another world and decided to use his wealth to get modern day technology and tools to help the locals out. Highly recommended for entertainment value.
12. Primitive Technology: Build Water Wheel Fish Pond Full Part A video where a couple of guys form a fish pond including a water wheel using nothing but primative tools and what's available to them in nature. Highly recommended against if you're looking for entertainment.
13. How Flour Is Made At A Traditional Watermill A video talking about how flour is made at a traditional watermill, focusing largely on the watermill but contains some mentions about the process of the flour. Not recommended for entertainment value.
14. Homemade Water Mill A video showing a homemade waterwheel at work, included largely to help give an idea as to how to utilize waterwheels in more complex ways even without smithing techniques needed for gears available. Highly recommended against if you're looking for entertainment.

[2095conash]

So, we've covered some basics in food and survival, that I think I should now address a matter that probably should have come before the agriculture bit, water! While not quite as important as air or shelter in a harsh environment, you can go 3 days without water and so if you get stuck in an especially harsh isekai and aren't lucky enough to have the 'create water' cantrip you've got three days (beyond whatever supplies you might have luckily gotten) to get yourself some water to drink... Though if you do end up in such a world, the populace will probably become so dependent on the local religious groups for their divine magic that they may very well not know how to get water any other way, so whether it's for self survival or to try to wrestle power from a corrupt religious institution you may find yourself in need of some of this information!

Water Acquisition

• Finding rivers/streams- So while I don't have any direct references to this specific situation what I have found generally indicates that if you want to find streams what you should do is try and follow the lush vegetation and animal tracks, typically going downhill as that's where the water is going to be heading. When you have to stop and rest (sweat may help you move for longer but it comes at the cost of losing water) make sure to listen for the sounds of running water. Birds will try to fly towards sources of water at morning and dusk so keep your eyes out for them as it could help you quite a bit. That said, do not drink from the water, especially if it's not moving as it's likely to double as a sewage system for a lot of animals with a hardier constitution than yourself and become a breeding ground for all sorts of bacteria that will do a lot of damage to you. We'll get into low-tech filtration methods later to help get out any physical matter that you don't want to be drinking, but the key for purification is to boil any water before you drink it to kill anything that would risk you doing harm, it's better to lose a little water to steam than lose a lot of water to illness.

• Groundwater and others- While rivers and streams can probably get you access to plenty of water (albeit with a bit of filtration) you may find yourself in a situation where the local deity/random chance that brought you to this world isn't quite so charitable and drops you out in the middle of a wasteland, as seen in both Moon-led Journey Across Another World and in Paradise of Spirits and Ideal Life of Different World (which does actually involve getting groundwater to help survive while Moon-led Journey was solved by running into other people), in these environments relying on finding other people or sources of water above ground can become a fools errand that you will die before accomplishing. As such, it's good to keep in mind good ways on how to find and access groundwater so I suggest checking out this video. The video also addresses solar stills and transpiration as other methods of getting water, which can be useful. These various methods can however be a bit more predicated on the resources and items you have available to you, but the video addresses the various methods simply enough that hopefully if you do get isekai'd you'll be able to remember at least one method that'd be useful for your purposes! I will also briefly mention that you shouldn't discount cutting open trees or plants and getting water from them more directly (coconuts for example could be useful for this) however at this time I don't have enough information or tips that I'd be confident commenting further on the matter, just keep in mind that it is possible if you can find any plants that would have drinkable water in them (like bamboo or banana trees).
  
  Now, while that was all talking about simply getting water for survival purposes, let's take it a step further and look at how we can use our modern knowledge to make the lives of the villagers who will presumably treat you like a god that much easier, with the knowledge of hand pumps. While it's not discussed in detail Record of My Reincarnation in Another World makes a point of introducing this into their world and talks of how it's 'a simple thing'. So I looked it up, and while making the frame work out of a sturdy material might require that you're at least in the bronze-age, looking at the actual mechanics as highlighted in this video the mechanisms which make this little feat of magic (as it may appear to some) work isn't that complex, largely relying on utilizing both simple machines and pressure to defy gravity much easier than your typical well. This little invention will probably be a lot safer from copy-cats in an age before intellectual property laws due to how even taking it apart may not reveal how it works due to it's reliance on pressure (and thus cutting it open may very well prevent it from working), but do be careful with how you explain it to the locals as you want to make sure you at least don't piss off the local religious beliefs.

• Filtration- While no replacement to boiling water, there's a lot of situations where you can find yourself with water that is just filled with a lot of gunk that while not alive, can do you some serious harm if left in the water. To that end this video discusses how to setup a charcoal filter rather well (if you don't have cloth to keep the charcoal in place a good sized rock will do fine since you just need to make sure it doesn't get clogged), though if you want to setup a fountain to filter your water for the purposes of a town this video demonstrates digging up groundwater, setting up a well, and setting up a large-scale filtration method, though I would highly recommend watching it at two times speed or even skipping around in general as it's rather long and the only information you will get is from watching. Keep in mind though that you'll want to run water through a charcoal filter a few times after you set it up to get it started, but as long as you filter and boil your water you should have access to plenty of safe drinking water for your own consumption.

• Creating Rain- So as I was sifting through some of my manga for the next post, something caught my attention. In "I Won 4 Billion in a Lottery But I Went to Another World" in chapter 2 the main character gets the village to start a fire in order to make it rain to help them get water, however since it's only briefly touched on and how you do it wasn't really explained so it never really stuck with me (perhaps the web novel goes into more detail), so I looked into it and it is a real thing. So, while this can help you with water keep in mind that as highlighted by the video there's a few risks associated with this, and don't expect to get results quite as quickly as they got in the manga. Best as I can tell, it's not completely understood how to reliably make them form, but what is understood is that water vapor from burnt vegetation or volcanic eruptions helps contribute to them so make sure that if you want to create a Pyrocumulus Cloud that you include some non-dried vegetation in your fire. It is also believed that ash in the air from the fires or volcanic erupts helps condense the water vapors, but the best info that I could find isn't too clear on the matter. Either way, if you try this you'll want to make sure that you use a controlled fire to make sure that it doesn't grow out of control. Since this is very largely dependent on the formation of clouds, you may not find a lot of success using this method out in the desert where the supply of water both in the air and ground can be very limited (likely due to mountains blocking rain clouds out of the area).

References:

1. Moon-led Journey Across Another World Web novel, Light novel, and Manga. Isekai where the MC is getting sent to another world, but goddess of the new world thinks he's ugly so steals a couple more people from our world and tosses MC off to a corner of the world. Slightly recommended for entertainment value.
2. Paradise of Spirits and Ideal Life of Different World Web novel, Light Novel, and Manga. MC was on a shopping trip, gets isekai'd into a wasteland with no idea what's going on (yet somehow having overpowered equipment in his inventory), has to survive with the help of some spirits. Recommended for entertainment value.
3. How Do You Find Water In The Wild? a youtube video. Informative video about how to find drinking water, setting up a well, how to setup a solar still, and how to use transpiration to get water from plants. Slightly recommended for entertainment value.
4. Record of My Reincarnation in Another World Light novel and Manga. We're looking at the rare double-isekai, where two people who are about to die (a master commander from long ago and a highschooler) have their souls merged into a noble putting three people into the same body. Well recommended for entertainment value.
5. How a reciprocating pump works a youtube video. Informative video showing how a reciprocating pump works and showing the internal workings of one, with explanations as to what's going on. Slightly recommended for entertainment value.
6. DIY: Make swamp water drinkable a youtube video. Explanation and demonstration on how to setup a charcoal filter, albeit designed more for a zombie apocalypse, and helps show the differences of the before and after. Not recommended for entertainment value.
7. Primitive technology: searching for groundwater and water filter a youtube video. A video demonstration dialogue of a couple of guys digging and building a well then setting up a fountain like filtration system. Highly recommended against if you're looking for entertainment.
8. I Won 4 Billion in a Lottery But I Went to Another World Web novel and Manga. Isekai where the MC won the lottery, moved into a house his dad had, then found a locked room that lead to another world and decided to use his wealth to get modern day technology and tools to help the locals out. Highly recommended for entertainment value.
9. Science Behind: What are Pyrocumulus Clouds? A clip from a weather channel explaining what Pyrocumulus clouds are and some of the impacts they can have. Not recommended for entertainment value.
10. Flammagenitus (cloud) a short wikipedia article about Flammagenitus or Pyrocumulus clouds. Not recommended for entertainment value.

[2095conash]

Right so, now that we've dealt with the all too common but rarely fully explored details of 'crop rotation', I wanted to explore a certain kind of scenario and the various pieces of information that I've noticed that can help with it, a scenario where the world you end up in does not have humans (who we assume will be there, will discuss scenarios without humans later) as essentially the apex predator of the entire world. For this we will be avoiding situations like No Game No Life where the various non-human creatures you're competing with are basically "Humans and then some", as evolutionary speaking a lot of the races you will see in these fantasy settings like elves, angels, dwarves, and demi-humans (sometimes demons as well) tend to have a lot in common with humans leading to a lot of the various advantages humans have over say the wild life in our world gets ignored. Some of these tips can still be used against some of the more 'monsterous' humanoids, though effectiveness will vary, and make sure to keep in mind that relying simply on this stuff will not guarantee that you manage to take over the world, just give you some ideas to work with when coming up with plans on how to deal with various threats.

Fundamentals to Overcoming Monsters

• Human unique strengths- The first place to start with to overcoming monsters or various 'wild' creatures you might encounters is to understand the strengths that humans in our own world have that let us manage to overcome Lions and Elephants back in Africa, this video should serve that purpose. See, while tool use has gone a very long way in helping us get to where we are, there are a lot of different animals out there which also have tool usage yet haven't gotten quite the global reach that humans have, a big part of this is because thanks to our longer legs and shorter arms our center of balance is much better suited for weapon use in general, though projectile weapons were the primary choice pack in the day as it'd allow us to keep our distance from animals that could easily kill us. See, when it comes to other primates that can use tools a lot of them have arms long enough to use to help them with walking, so if they try to put their full force into their arms to throw a spear or swing a sword they will be knocking themselves over with every attack making weapons just unusable for them, birds run into a similar issue though theoretically they could utilize weapons while they're flying as it leaves their talons free to move and being aerial would off-set the balance issue, but it'd be an incredible investment in energy and resources that it seems unlikely that birds that could craft unnatural weapons would be able to survive alongside birds reliant on natural weapons. While not touched on in the video, the use of fire and agriculture were also very powerful applications of tool use that's not seen in a lot of other animals, as it allows us to take advantage of being omnivores to acquire food safely as well as gives us a very potent tool at warding off threats (and overcoming our lack of night vision). On a bit less obvious side of things, the ability to sweat is also a very potent and uniquely human (in our world) advantage, as it would help allow you to either out-run any creature with fur that doesn't have enough speed to get you fast enough, and should not be ignored. However the video also outlines several weaknesses that humans typically possess, so if you're really dedicated about preparing to survive essentially out in the wild, knowing how to effectively create weapons, camouflage, and some measure of protection (basic clothes would count) would be very important. Still, the uniquely human abilities are often overlooked in fiction altogether, so don't forget that if you're being chased by a were-wolf that the ability to sweat while it will have to stop and pant (theoretically) may very well save your life! Though it should be noted, as was pointed out at the end of the video is that animals that are given the opportunity to evolve alongside humans will generally become well adapted to their strategies, as they have had the years to develop counters to the human advantages as humans were themselves developing them, so it will be important to note that if you can't bring in enough knowledge the overcome the various threats humans face in the ecosystems they inhabit, you may want to try exploring out and finding new areas to inhabit and build up resources fighting against monsters that would be taken completely by surprise by creatures who possess these abilities.

• Dealing with enemies- Now while having an assortment of tools can be good, you're also going to need to know how to use them effectively and to do that you're going to need to understand your opponent. As such, it's good to know the general combat strategies often used in the world as well as their strengths and weaknesses, which you can find here. Being able to identify where any given monster falls will help you greatly in properly countering them, but make sure that you have all the information that you can on your target to prevent planning to deal with say the horns of a deer but then getting overwhelmed as it fights you off with a series of attacks from it's forelegs, and if you end up in a world with magic all of the attack options at the disposal of the enemy may not be immediately apparent, however the basics of these strategies should typically apply on a magic scale as well (where projectile magic will probably take a lot more energy than magic that's being used to make you go faster, making magically enhanced 'rush-down' tactics still probably effective against magically enhanced 'projectile' attacks), but simply being aware of the basics of these sorts of tactics and identifying them can give you a huge advantage by bringing tools and abilities designed to counter what the enemy has (better defense against an agile opponent, disabling abilities against mid-range opponents, ranged weapons against grapplers, etc.) and if you can apply magic along a similar line of reasoning to be able to better counter their strategies. Though you may want to be careful of dragons, having a ranged attack and armor could leave them as pretty deadly based on this analysis since the common counter won't be too effective there. That said, that are some enemies that will probably be especially difficult to deal with so it'd probably be good to rely on more advanced tools/tactics for specifically taking them down, I would say that Goblin Slayer covers a nice variety of tactics and strategies that can be useful when dealing with enemies as well as showing why not to underestimate your enemies, but if you want to go a bit more in-depth and try utilizing poisons or other tactics Exterminator may be more up your alley as it at least brushes the topic of creating some poisons to deal with enemies based off of how you'd do it in our world (though at times magic is requires for some of the precise strategies used). Generally speaking, you will probably have to get creative to be able to consistently deal with your enemies, so make sure to try to try to get as much information as you can to help ensure that any tools you bring will help you accomplish your goal.

• Domestication- One of the biggest things that helped humans grow to the level that we're at is the domestication of animals, if you're looking at effectively putting humans at top in a world without any other sapient creatures already there, the ability to domesticate the wild life around you will be a huge boon to your efforts, so it's best to try to understand how to identify good animals/monster to try to domesticate from bad ones, this video should serve as a good starting point. In it, it lists out the general requirements that you'll need to find in a creature if you want to domesticate it and explains it. I could repeat the major points here, but honestly I feel the video does a very apt job and explores the depth of it much better than I could so I'll be continuing on assuming you've seen it. So after knowing the requirements to try to domesticate an animal (or try taming them in the case of the elephant) it'd be good to try to identify what you're looking to have to accomplish whatever your society is lacking, from horses for mobility, dogs for herding, raptors for hunting, camels to help deal with the environments you'll be in, there's a lot of different things that you may want to get some wild-life helpers for, and this video talks a bit more in-depth about some of the various advantages that you can get from animals (though it skips over dogs and cats, though cats have more tamed us if anything) so I suggest checking it out for a breakdown of a few different animals that could be useful and some pitfalls to avoid when it comes to trying to pick a 'teammate' as it would claim. In a world where humans are having trouble struggling to get by, being able to domesticate (or at least tame) some of the local monsters by identifying which ones would be more or less susceptible to these tactics, how you'd go about it, and how useful they'd be for your goals could give you a huge advantage in trying to bring another world under human control (or at the very least make it so that you and your theoretical harem don't have to worry about monster attacks all the time). Though that said, while domestication can bring a lot of advantages, you will need to be careful about starting some kind of 'dragon-pox' plague if you start domesticating dragons, a good video about how wide-spread domestication can affect societies as a whole can be found here. A later section will go into more depth about how to minimize or outright avoid a lot of these potential problems.

References:

1. No Game No Life Light Novel, Manga, and Anime that regularly gets into extreme fantasy Death Note style 'games'. An Isekai about a pair of siblings who essentially have the super power of being unbeatable at games get transported into a world where everything is decided with games and have to save imanity (humanity) from being wiped out basically. Brought up in passing as an example of a scenario where humans are not in charge but the creatures above them are basically super-powered humans as an example where these tricks likely wouldn't help. Highly recommended for entertainment value.
2. Are Humans OP? A youtube video examining human's strengths and weaknesses as well as their rise to global power heavily coached in game terminology. Used to better highlight the unique characteristics of humans such as our center of balance and ability to sweat as well as used as a jumping off point to discuss tool-usage and some other survival strategies that could be used. Well recommended for entertainment value.
3. The 4 Animal Combat Styles a youtube video examining the basic combat strategies animals in our world use, their advantages and disadvantages, and gave some examples looking into them heavily couched in game terminology. Used to help better highlight some basic strategies that other world monsters would probably employ and how to deal with them. Well recommended for entertainment value.
4. Goblin Slayer Light Novel, Manga, and Anime that details some adventures of a character who does almost nothing except hunt goblins with some looks into the preparations and thoughts he puts into everything he does. A fantasy story that's heavily implied to take place inside a DnD campaign but with no 'players' seemingly present is distinctly not an Isekai. Referenced as something that handles looking at how in-depth knowledge of your enemy and proper preparations, as well as a bit of a strategy, can go a long way. Highly recommended if you aren't bothered by the early depictions of rape and murder.
5. Exterminator Web Novel, Light novel, and Manga that follows a main character who used to be an exterminator as he employs his skills and knowledge from his old life to get by in the new world that's he's now apart of. Definately an isekai. Used as an example as to how people could potentially work on making poisons and other sorts of large-scale traps to help better deal with monsters, as it even includes recipes to go along with it (though some of the tricks employed are based on stuff only available in that world so your results may vary). Not particularly recommended for entertainment value.
6. Zebras vs Horses: Animal Domestication a youtube video examining what it takes to domesticate animals and explaining why humans have domesticated horses but not Zebras. Used basically entirely to explain how it all works. Highly recommended for entertainment value.
7. What's the Best Support Class? a youtube video examining various domesticated/trained animals and how they get along with humans, their uses, and a few more important details to working with them that CPG Gray didn't include, the video is heavily couched in game terminology. Used to help reference the idea that people should think carefully about what they need and what the various monsters may offer when it comes to domesticating/taming them. Well recommended for entertainment value.
8. Americapox: The Missing Plague a youtube video examining some theories about how plagues come about, though said theories have been criticized so I can't vouch entirely for how accurate these theories are. Used to demonstrate both that domestication of animals can rapidly grow society as well as create the perfect environment for plagues to both begin and spared. Highly recommended for entertainment value.

[2095conash]

Often times in Isekai stories you'll be transported into some medieval style worlds, with a lot of progress filtered through the use of magic rather than a full understanding of the world yet keeping a lot of the same core understandings of our world. This is not always the case, but it can easily lead to a world where our modern agriculture (one of the biggest advantages that helped us have such a dominant hold over the world of today) methods are far more advanced than theirs. This is not always the case, whether they are assisted by magic or if it's just not an Isekai that cares to explore the ideas of applying modern knowledge and innovation into a world lacking it. Sadly I don't have a lot of good references of media that tackle this specific part of modern knowledge and innovation in a way that I find adequate, but with how often I see it glossed over, I figured this was as a good a place to start as any!

Basic Agricultural Tips

• Crop rotation- Yeah this is an easy one, just about all Isekais out there that have any form of future knowledge advantage will mention crop rotation at least once, but I typically find their dealings with it very lacking and generally just say 'Crop Rotation' as if it's a magic spell that instantly gives you a permanent +500% buff to your agricultural abilities. Crop rotation is far more complex than just saying a word and solving all your agricultural needs, and the only piece of figure that I've seen tackle the issue with a level of depth that I appreciated was the official Maoyuu Maou Yuusha were they talked about it early on, mentioning both a three-crop rotation (wheat in the summer, barley in the winter, and resting afterwards) and a four-crop rotation (barley to clovers to wheat to turnips) as well as how potatoes can be a great vegetable to help with crop rotations at a later point. For those of you unaware, the thing about crop rotations is that since crops need various nutrients to grow if you grow the same crop in the same spot year after year eventually there won't be enough nutrients to sustain it, so while the simplest solution is to till your entire field and only use half of it switching which half is 'resting' to recover nutrients, if you plan things out to use crops that consume or replenish nutrients in a smart way then you can greatly increase your crop yield without worrying about them running out of nutrients. Now, while from my research the various suggested rotations in Maoyuu would be good as it tries to balance not only the nutrients used, but also the types of crops that you pull out (mixing crops for food, crops for livestock, and what you can grow in what season) I personally was not satisfied with simply memorizing some kind of crop rotation. See, over the centuries of human agriculture we have changed quite a bit of foods to be better suited for our consumption through selective breeding, as seen here, this is also before getting into the fact that you're heading to another world entirely, so the thought crossed my mind, 'How would you figure out a working crop rotation for a world with entirely different crops?'
  
  So to that end, I tried to find good information about what goes into determine what kinds of crop rotations to use, and the best I found was this video. To keep things simple for people who'd rather not go through the video, some tips to keep in mind is that a good way to determine what nutrients any given crop has is to base it off of the bugs and other pests that try to eat it, crops that require similar nutrients (like tomatoes and potatoes) will have similar pests, so a quick conversation with an experienced farmer in your brand new world about what pests like what crops will give you a good idea what nutrients they use, on top of that over the centuries people have had various systems like rotating 'fruits, roots, and leaves' (sometimes with legumes in the mix, sometimes not), I'm not quite sure if trying to mix things up along those lines as well as with the pests will give you better results, so if you're the one going into an Isekai I'd suggest maybe try talking some with the various farmers around to see if there's any objection based off of experience and if not just keep trying to mix things up until you get a system that works. Just because this theoretical world doesn't have wide-spread crop-rotation doesn't mean that the locals don't have more experience with these crops that aren't from our world.

• Scythes- Another quick agricultural tip is the usage of scythes. If the Isekai you are transported to has people largely using sickles to harvest their wheat or other such crops, scythes will tremendously speed up the process. This shouldn't be quite as complex as crop rotations because if they already have sickles (which if they don't and you plan to introduce them to brand new tools, make sure you've got some kind of curved blade to help with harvests) then you're mostly looking to just make a bigger version of it, however simply having them won't help much if no one knows how to use them properly, after all the sickle allows them to grab and straighten the crop directly before cutting it, so by switching to a two-handed tool they aren't able to get the same kind of leverage as before. So if you plan to invent scythes (and maybe make a quick dollar before some merchant comes along and steals the idea) make sure you know how to use it yourself first, and to that end I think this video gives an adequate demonstration as well as makes clear the value of having a second handle to help you get the kind of leverage from your own body that you're losing from not being able to handle the crop: skip to the 1:20 mark if you just want to see it in use.

• Thinning out forests- One thing that's not too uncommon in just about any fantasy setting are elves and their eternal forests who fight against any sort of cutting down trees. Now, I personally don't find this too likely myself, as Genjitsushugisha no Oukokukaizouki pointed out it's very important to regularly thin the trees. Early on in it they talk about the idea of thinning out forests (cutting down a moderate number of trees regularly) in order to help maintain them, this is because if left unchecked the older trees will spread their leaves to an extent that will block out the sun making it difficult for younger trees or smaller plants to grow and without the undergrowth will struggle leading to less water retention (and could put some of the other plants at risk of dying out but that wasn't mentioned) and causing more landslides, on top of that trees that are close together will interfere with each other's group (fighting over nutrients, water, and space for roots) leaving both far more fragile and will easily be destroyed by wind or snow, both of these issues put together means that strategically cutting down trees can help lead to a more stable ecosystem as a whole while also providing those living there with lumber and other resources that could be used for trading or other purposes. Any magic that these theoretical elves could provide may change the necessity of this, but that's an expenditure of resources ultimately made in defiance of the natural order, as the circle of life is rather dependent on nutrients and matter often shifting forms and moving from one organism to another, so ultimately any group that values nature so highly would be well served to help keep this cycle going by thinning out the trees some and using their magic in other ways.

References:

1. Maoyuu Maou Yuusha Light Novel, several Mangas, and Anime (anime not as informative) that explores a lot of ideas. One of those 'two worlds' Isekais with free-ish travel between them, the demon lord often acts like a Wikipedia style Isekai protagonist. Used to give example of crop rotation explained thoroughly in media as well as gives a few examples of crop rotations based off of our real life crops. Highly recommended for entertainment value as well.
2. Vegetables Info-graph Basically lists a bunch of different vegetables as we found them in the wild vs what they've become today, though I have not verified the accuracy of it's information myself. Used to demonstrate how even in our own world, selective breeding and raising of crops/livestock can result in wildly different things over time and as such you should not assume that whatever world you theoretically end up in will have the exact same crops as our world.
3. Crop-rotation video a youtube video that looks into crop-rotations, the value of them, and the value of using a computer program to plan out your own crop-rotations as well as some of the pitfalls you can run into with planning a crop-rotation. Used as a reference point to gain some basic information that can be used as to how to plan our a crop-rotation for otherworldly crops without technology. Not recommended for entertainment value.
4. Scythe usage video a youtube video that looks into scythe usage, demonstrates how to use it, and talks about various benefits of it. Used to help demonstrate how to use a scythe for references sake as the usage of a scythe and sickle vary from one another. Not recommended for entertainment value.
5. Genjitsushugisha no Oukokukaizouki Web novel, Light novel, and Manga that explores a lot of ideas. One of those royalty summoning a hero to fight the demon lord, but in this one the main character ends up becoming king of the country instead leading to a bigger focus on running a country, politics, and war. Brought up as it explored the idea of thinning out forests to help maintain them and gave some reasons as to why this is important. Well recommended for entertainment value.

[2095conash]

So, I tend to enjoy this sorta third wave of the Isekai setting that has been cropping up in a lot in Japan, and let me tell you, I have read a LOT of trashy Isekais in the process, but something about it just really clicks with me... It's probably something about the wish fulfillment, iunno, but that's besides the point. See, in my time reading these Isekais, it can be a lot of fun to read up on all the information or ideas that sometimes these characters bring in from our world to give them a bit of a heads up in their new world, to the point that if they explain or use it well enough that I'll forgive a story that treats it's protagonist as if they're a walking wikipedia with no explanation, and it's sparked a bit of a curiosity in me at times to look into these matters and try to figure out how all this stuff works. All of this has left me wanting to take all this poorly researched information and assembled it together, some people may have their zombie apocalypse preparedness kits, I have taken to putting together a bunch of information and ideas to help survive in an Isekai, and hey if that's not really your thing feel free to just look at some of my references for some manga recommendations where I either pull information or scenarios from (not all of them are Isekais mind you). If this sorta thing seems fun to you as well feel free to help contribute some information yourself or let me know if I got something wrong, while I will try to keep the information here accurate I'm sure that I'll be getting some stuff wrong. Without further delay, let's get into this!

Basic Agricultural Tips
Fundamentals to overcoming Monsters
Water Acquisition
Water Application