掲示板 Forums - The ~ていくform.

I think these two following sources will help you understand the usages perfectly!

https://youtu.be/5XUmIsGslGM?si=dMelTgf0RcVx3yz3

https://www.tofugu.com/japanese-grammar/teiku-tekuru/

Okay, I saw your example sentences for each grammar. They are "grammatically correct" but 4 of them felt "weird/unatural" for me. But I was unable to pinpoint exactly why nor could I find any formal explanation. So I will rely on renshuu sentence database instead.

But first, the basic literal usage/meaning of both expressions should be very clear to you and you should be able to distinguish them from the more abstract usage. And I'm not talking about a grammar understanding point of view but a pratical point of view. And if you need to study 10 or 50 sentences for each case, then so be it. Things like 帰っていく vs 帰ってくる should obvious before the more abstract usage. Not only because it will reduce your confusion (because you will be able to distinguish them) but also because those "basics" usage will help you to "construct" and understand the more abstract usage. To give you a few example:
水を取って来る ("take water" and "come back")
トイレ行ってくる ("go to the toilet" and "come back")
何かを持って行く ( "hold something" and "go")
何かを持ってくる ("hold something" and "come back")
歩いていく/歩いてくる ("walk" and "go"/"walk" and "come back")
Etc.

Honnestly the first case of each grammar point should be those usages with tons of sentence examples instead of the "change over time". If those are not completely clear or obvious, don't hesitate to ask!

Now, for the abstract usage of both expression, first, you can think of ていく as "moving forward", "progressing", "advancing", "taking a step forward". Or a bit literaly "Moving away from the current situation" (in some case). For example:

• 痛みが引いていく: 痛みが引いて -> the pain is pulled away/removed and the "situation" is moving toward that result. Or, a bit like 歩いていく (go somewhere by walking), you move forward and at the same time, the pain disapear. Like, you go somewhere and at the same time, that other happens. You could also think "As things progress/move, that other thing happens too".
• 痛みが消えていく: same here "the pain disapear" and the situation is moving toward that result.
• 問題は増えていく: "the problem multiply" and the "situation" is going in that direction.
• Etc.

If you struggle with that, remember the "taking a step forward". It's still the 行く that you know. It's just used a bit abstractly.

For てくる, 80% of the time, it's like the "situation come to you". Like it happens without anyone intention to do so or by surprise. Or simply, to talk about the result. It's not really about change/process most of time but it's more about an event. Well, more exactly, in the case of てきた. Like:

• 分かってきたわ。: "I understood!" (or the "understanding" came to me)
• その島が見えて来た。:"That island became visible" (or the island "came" to us and "decided" to become visible... it was a nice island)
• 空が曇って来た。: "The sky became clouded (or a clouded sky "came" to us)
• Etc.

It's still the 来る that you know but used more abstractly. As in something coming to you. Like you could say 友達が来るよ, "Friends are coming (to me/where I am)". But instead, it's a situation/state/etc. that's "coming" to you. It's weird but it's also as weird as using "hard" to mean "difficult" for non native english speaker. You just need to get used to it.

As for the few case where ていく and てくる can be interchangeable, if you kinda understood what I said, you should be able to understand them there too.

• 世の中は、変わっていく。-> The world is moving forward/progressing and changing -> The word is changing
• 世の中は、変わってくる。-> A changing world is coming -> The world is changing

That make no difference in english but that's just because in english, you don't say things like 帰って行く and 帰って来る. That nuance is not needed or normal in english. But honnestly, there are not really different from the more abstract meanings/usages.

Oh also, at the beginning, I said that a few of your sentences felt weird for me but honnestly, I don't think I can explain it properly. I have multiple explaination in my head but... Oh well, I think I will ask some japanese friend instead if I have the occasion. In the meantime, just search "勉強していく" in the dictionary. Renshuu has about a 1000 sentences for "勉強" but when I search for "勉強していく", I couldn't find a single sentence... So yeah, something is weird here x). Same for "料理していく".

Anyway, hope it will help at least a little bit.
頑張ってね

Happy to hear that it was useful!

"So that ていく is kind of directly proportional where both of them goes in the same direction ie moving towards the result?"
What goes in the same direction exactly? Could you rephrase your question or develop a bit more? I need to understand your point of view a bit more to give you an appropriate answer.

"Also thx for looking at my sentences, I will try to understand it again.."
More than understanding, you probably need more "experience" with japanese. There's a perfect japanese proverb for that btw.
習うより慣れろ -> Rather than learning, get used to it!

And the reason why it's important is because of stuff like "hard" to mean "difficult" in English for example. You won't find an explanation to that kind of things in grammar. But languages are full of that stuff. You won't be able to understand it until you have the same "reference" as Japanese people do. Or perspective. I don't really know how to call it.
That is what people need most of the time when they struggle or are stuck on grammar. They don't need more understanding. They need more practical experience, to observe how Japanese is used by Japanese. There is even another japanese proverb for that!

見て盗む -> Observe and steal (techniques, knowledges, etc)

I don't know if you already experienced that but trust me, it can be really frustrating later if you ignore that. Like, you spend 1 month on some grammar point, give up, study basic sentences, read or watch japanese contents for a few months and then one day, someone ask a question about that same grammar point and you realize that you're able to understand it. Honnestly, it's so annoying when I think about the time I spent on some grammar point...

Anyway, to sum up, when you're stuck on grammar, give up, study some sentences until it become obvious to you that should use that particular pattern in this specific case (even if you still don't understand perfectly why). You need to feed your current understanding of japanese with practical and particular case. That will fill the gap that grammar doesn't really explain and you need that to "refine" your understanding. Also, it help with confidence. Because when you've seen the same pattern 50 times, even when you still unable to fully understanding it, you will at least know that you can use it like that.

Why do japanese streamers always say 水取ってくる when they go AFK to take some water instead of something like 水取って戻る for example? I had absolutely no idea. Didn't seems wrong in terms of meaning. But I never heard it. But 水取ってくる on the other hand, yes. Countless times from clips on youtube, japanese friends online and I also used it quite frequently. I know how to use it or when to use it but don't ask me for a full understanding for a lot of those sentences. Like the "勉強していく" case. And accepting that I can't understand or explain everything right now was one of the best thing I did for my Japanese journey. Should do it even more but I can't help myself since I'm overthinking idiot.

Anyway talked too much (again), so I will stop here x)

@Shamugan :
What I meant by both is the passage of time and the resulting change? Like I can see two things progressing, the situation and the change..
Thank you for the explanation again and phrases I guess 😄. I really need to grasp more .. never tried stuff that you said. Could you refer me to some videos or some titles as to I can start?

@ギョルギ九十三 :
Thank you for looking at my sentences and providing me sentences ! From what I can see there are two verbs now being added in the sentences?? I think I got the wrong idea of this grammar point lol...
Now what I think is what if all my sentences are wrong lolll 😢
When you learn a new grammar point, and when you add a new sentence in the grammar library how do you know like is it correct or is it wrong? Do you need someone to correct it or you have to go by intuition or rules or do you need more information ?
Ahh did I get all the stuff wrong? 😩

Ah, I mean, if it make sense for you to distinguish those, yeah. But "situation" here was more like the "end-point". For example,
A -> B
A and B are "situation". "change" is just the arrow.
In 「痛みが引いていく」, 「痛みが引いて」is B, or the "resulting change" if I use your words. And when you add いく, you add the arrow, the "passage of time".
「痛みが引いていく」 is just "-> B"

I also tried to avoid the word "change" on purpose. I think one of the main reason why a lot of people get confused by ていく and てくる is because they are explained in terms of "change". And, for example, on renshuu you have "Shows a change over time" for both of them. "Great, what is the difference then?" is what most people think and are bothered by.

And that's why I gave you an "alternate" explanation. But you shouldn't try to mix those explanations! That explanation was just here for one thing: allowing you to distinguish ていく from てくる. Don't try to generalize that or hope to completely clarify those! It's like that "Is it a 6 or is it a 9?" meme:

What you're basically trying to do is find a word to talk about it, that you know, and which is neither 6 or 9 and both at the same time. I can't do that. All I can do is tell some people "Hey! Don't you think it's 9? And it's a 9, then it means that..." when they are stuck, for example. And beyond that is what scientist basically spend all their lives doing. Trying to solve the "Is it a 6 or a 9?" question. There is a point when you're studying grammar where you should stop thinking because it's basically "scientist" territory and that will just confuse you. Don't try to overthink grammar and get what you can get from those explanations (especially on the internet). Otherwise, that when you start to make mistakes. Why? Because you used "9-type" explanation/thinking while it should have been a "6-type" explanation/thinking. "勉強していく" should makes sense right? Well, "bad luck" here, on the 1000 sentences that contains "勉強", there is not a single that contains "勉強していく". Is it a coincidence? Is there an explanation for that? No idea, I can't even tell you for certain if it's really "weird" or not.

But natives, even when they're completely unable to explain it, they can still use those patterns correctly. Why? Because even while being unable to put it into words, they can percieve it both as a 6 and a 9 at the same time. And use it accordingly.

"Ahh did I get all the stuff wrong?"

NO! You're just confused by multiple point of view. Each view is neither right nor wrong. Just different.
So to conclude, just 3 advises:
- Don't overthink grammar. Past a certain point, it's linguist detail level and they disagree a lot with each other.
- Don't mix explanations. When you try a new explanation, try to think from that point of view only.
- When you're studying a grammar point, study 50 or 100 sentences that contains that grammar. That will "complete" your understanding. But only like a native. Aka: they can use it but not always explain it (even most of the time not explain it).

On that note, I will answer also one the question you asked to ギョルギ九十三 because I think it's important
"When you learn a new grammar point, and when you add a new sentence in the grammar library how do you know like is it correct or is it wrong? Do you need someone to correct it or you have to go by intuition or rules or do you need more information ?"
I don't believe any of my sentences are correct. Except the ones that I already exposed to more than 1000 times. Like
水を取ってくる. I'm confident with that one because I used it more than, I don't know, maybe 500 times with natives? And for most of the sentences that I used in my explanation, I made sure to double check with renshuu sentence dictionary. Most of them are even just straight up pulled from renshuu dictionnary. Because even if I have some degree of confidence, I'd rather not take the risk of giving you a wrong example. Even with just a 1 in 1000 chance, I would rather not take the risk. Because I'm still learning. I won't ever be a good judge while it's still the case.

So when I want to create a sentence from nothing, I usually just search it for examples in renshuu. Especially when I'm not sure or not used to it. Like for 勉強していく. I was not familiar with "勉強していく" at an intuitive level (in my internal sentence databank, couldn't remember a single sentence with that... despite talking with a lot of japanese learning english). So I searched for it and did not find a single sentences. In that kind of case, I just stop there and stop thinking about it. I often give up. Because I know that what I need is more time and practice 99% of the time. So unless tons of thing pile up (intuition, grammar understanding, etc).

The only time when I don't bother about being correct or not is with natives. Because, when I make a wrong sentence, they either look at with big eyes or laugh at me for 10 minutes. So I know when I'm "too much" incorrect in those cases.

"Could you refer me to some videos or some titles as to I can start?"

Sentence schedules with the basic setting only. That's where I started. I got frustrated with grammar, so I completely gave up on grammar and just spend 8 month studying sentences. It made me "able" to speak japanese without understand how it works. And later, I started to study grammar again (occasionaly). What help me along the way was watching youtube and talking to some native. That's why I insist so much on the "don't overthink grammar". I literaly completely gave up on grammar. And ironically, that made me understood a lot of grammar point... I'm even studying grammar for japanese natives in japanese because of that. Without studying those sentences first, it would have been impossible.

Anyway, talk too much again x)