@duong091 @matt_in_mito
Hey and sorry for the slow answer 
I would say that the most common way would be ２時間ごとに。２時間おきに would be also correct, but it might cause some confusion sometimes.
I hope it helps,
Cheers!
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This seems like that age-old “how many days until something” problem, by which I mean stuff like this:
If today is the 12th of August and my birthday is the 14th, how far away is it?
The problem is that if you answer with days as discrete units, which they technically aren’t, you could have one, because there’s a day between them, or two, because 1 day away is the 13th, so 2 days away is the 14th.
What is the case for years, out of curiosity?
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I think a good way to think about is that, whenever that many of whatever you’re talking about happens, whatever you’re describing happens.
For example, 二日おきに would be the same as saying “once two days have passed”, whereas 二日ごとに is just “every two days”
So if our week is starting on a Monday:
- 二日おきに would refer to Wednesday as the day the thing is happening, because two days have passed.
- On the other hand, 二日ごとに refers to Tuesday, since it’s the second day on a two-day interval basis.
Does that make sense? @matt_in_mito @duong091
As a side note, I also read that the meaning may vary depending on the speaker.
So it’s always good to just ask for confirmation if you’re feeling uncertain. I’ll copy and paste the example from this reading:
例１）
Ａさん「この行事は、来年から２年おきに行います。」
Ｂさん「３年に１回ということですね？」
Ａさん「いえ。２年に１回です。２年ごとに開催します。」
Language is a living thing spoken by living things. So don’t think too hard about rules, just get the gist of it and try to use it!
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I want to suggest a link. The pictures here were really useful to me.
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Hello! Has the description been updated recently for this? I just reread it during a review and found lots of information I either forgot or was added in.
There is an example which I think is a typo, but if not, perhaps someone can explain? Towards the bottom it says this:
Continuous variables (things that are usually measured in fractions) - Either ごとに or おきに may be used. For example, seconds, minutes, and hours are usually measured by fractions, especially considering sports and racing. In this case ごとにwill mean ‘every second’, while おきに will mean ‘every opening of one second’ (disregarding all of the milliseconds, this means every second).
- 毎日まいにち2時間じかんおきに体からだを動うごかしている - I move my body every other 2 hours, everyday.
It says “every second” in the explanation but in the example it says “every other.”
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Hey there!
We recenlty launched in-house explanations, or Writeups as we call them, for every single N3 Grammar Point. You can read more about that here.
That’s probably where the extra info you’re seeing!
It’s mostly because our translations are based on nuance and meaning rather than being literal! By adding “every other” to the 2 hours, it makes it more casual which is the tone of the sentence.
Hope that makes sense!
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Thanks for the message 
. Every other and every second may be used the same way in English, although it could be regional as to which is more common.
Every other week and every second week are the same.
I think what they were saying was that it says “every other 2 hours”, which, in English at least, means every four hours - but in a way no one would ever word it.
They are similar, but not the same. Every other 2 hours means there is a two hour break, before something starts, and then continues for the set period of time. Basically continuing in a series of two hours, with 4 hours total. Every 4 hours would mean that something restarts/repeats at the 4 hour mark, not the 2 hour mark.
‘Every other’ is most frequently used with single units though (every other hour, day, week), as it does become confusing with larger numbers, exactly like おきに.
Sorry, I was only talking about the use in English, where every other just means one is skipped. That is, in the first two hours something would happen, then in the next two hours it wouldn’t, then in the third it would happen again, and so on, resulting in an occurrence every four hours overall.
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Prompt:
I change my smartphone at about two-year intervals.
My answer:
だいたい2年ごとにスマホをかいかえます。
Error text:
2年ごとに every two years. In other words the interval is one year.
Can someone explain this error text to me? 2年ごとに every two years is not a grammatically complete thought in English, so there’s nothing but more confusion to be had here. Further, for in other words the interval is one year, this second sentence is not anchored to anything, so it’s not clear at all what it’s referring to: the question or my answer.
It seems like the text is insisting “intervals of x” and “every x” mean different things? Does the prompt actually mean “every three years”? I don’t want to insist that my understanding of English is correct, but why trade in such ambiguous language to explain such an equally fraught concept in Japanese? The explanation and question prompts need to be extremely explicit.
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I think I understand how this grammar point is used, but am confused by the description; specifically the meaning of the kanji.
The current description:
“ While 置きに may appear to be an adverb, it is actually a combination of 置き, a suffix meaning ‘opening’, and the case marking particle に. 置きに (often without kanji) is an expression used to show that something happens ‘every (A)’, or ‘at intervals of (A)’.
As おきに is technically a suffix, it will be attached to the end of numbers or counters that it is highlighting as being an ‘opening’.”
—-
I have been looking for a dictionary to tell me that 置 means ‘opening’, but only find what I remembered, that being ‘put’ or ‘placement’.
This would actually make some sense if we thought of this as being derived from 置く, making 置き ‘a placing’ and 置きに ‘at placings’. However, the description says ‘opening’, so I’m left wondering if I just have bad dictionaries or if the description might be in error.
I wouldn’t have posted if my alternative theory didn’t make so much sense to me. Please give me any insight you might have about this.
So this is my interpretation of this grammar point:
I’ve read through the explanation, example sentences, links, and what’s in this thread, and what struck me with おきに is that the consistency between the explanations wasn’t what was being directly conveyed (discrete vs. continuous), but the fact that the interval to be skipped is always considered to be discrete and it’s whether or not the event can be considered spanned (i.e, a span of time) or spanless (i.e., a moment/instant in time) that marks the differences. This would explain why some sentences are naturally ambiguous, because some events can be grammatically interpreted as both depending on the context.
So for instance, if you have an event that you do every day that can be considered as a spanless moment in time, such as the time you wake up, feed your fish, etc. where you don’t naturally consider how long it will take, only the instant… then the entirety of that day has no chunk taken out of it from that event as, time-wise, it is dimensionless. Therefore, the discrete unit of the day is fully intact and can be considered as the interval to be skipped, leading to the “every day” usage that we see. Otherwise, if the event is considered to take an amount of time (spanned) for the purposes of the sentence that it’s in, then the discrete unit of the day has a chunk taken out of it and must be discarded entirely with the next discrete unit being used, leading to the “every other day” usage that we see.
This is a somewhat messy, definitely incomplete thought, so I’d appreciate it if someone could tell me if I’m missing anything with my understanding of this grammar point.
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Hi,
I am just learning this grammar point, and indeed it is confusing at first !
Thanks to the japanese stack exchange link I think I begin to understand, and then comes the first example sentence :
1時間置きに温度を測ってください
The translation is :
Please check the temperature every other hour
With what I understood, hours are continuous, so when we say 1時間置に, I understand “at interval of 1 hour”, so every hour (there is one hour between, let’s say, 1 pm and 2 pm, right ?)
So why the translation says every other hour, so every two hours ?
I think I am lost here !
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I have the exact same question. It also says that it is interchangeable with ごとに in this context, so I assume that it should be every hour instead. I keep getting this grammar point wrong and it’s driving me crazy 
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Hi, my teacher (native japanese) told me that it is every hour, yes. Other native people also confirmed this. It is a translation mistake.
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With おきに the meaning is always a bit unclear, and 1時間おきに is probably the most unclear case. For either interpretation, you can find native speakers who support it.
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I suppose the English translation is wrong in this sentence.
In English, this is what “about every 2 years” = “at about two-year intervals” means:
It does not mean “every 3 years”.
In Japanese, as far as I understand, and very helpful link by FredKore confirms it, this would be either 2年ごとに or 1年おきに
Edit: I don’t know if there are regional differences in English where “intervals of 2 years” = “every 3 years”, but for example this Wikipedia article says “The Olympic Games were held at four-year intervals” Ancient Olympic Games - Wikipedia
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I am going to rewrite the explanation for this grammar point tomorrow. I think I figured out what the confusion seems to be here. Ill edit this post again once I’ve made the change 
.
Edit - Rewrote a big portion of the description. It is longer now (maybe one of the longest on Bunpro 
), but hopefully makes a lot more sense. Basically all you need to remember is that ごとに = ‘sometime during (A), (B)’, while おきに means ‘sometime after (A), (B)’.
However, as the time/distance gets smaller and smaller, asking when exactly (B) happens becomes stranger and stranger, so おきに will tend toward the assumption of ‘exactly after (A)’.
@casual @nekoyama @Inounx @albcasahu. Feel free to let me know whether this is a better explanation, or worse.
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Looking at the example sentences within the description, I like how this one is clarified:
at intervals of one month. (Every second month)
If all test sentences that use the expression “at intervals” would be also clarified like that, that would help. For example:
at two-year intervals (every 3 years)
As is currently, I’m still not sure if you agreed with Eroliene’s and my feedback on that sentence or not. The Japanese one is asking for the answer 2年おきに, which means every 3 years, but the English translation means every 2 years.
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