English translation:
repeated at intervals
every other
every
at intervals of
Structure:
Number + Counter + おきに
Explanation:
おきに describes interval between events.
For continous variables like seconds, minutes, hours assuming that event is momentary Xおきに can be replaced with Xごとに meaning every X.
For discrete variables like days, weeks, months, stairs etc Xおきに cannot be replaced with Xごとに.
I really don’t get this one. How do we know the difference between ‘every’ and ‘every other’?
Hey 
1おきに can mean “every” or “every other(second)” by extension depending on a counter.
It is because おきに is used to describe an interval between events.
Rather than saying “every X”.
If variable expresses something that is continuous like meters, minutes and hours etc 1おきに will mean "every second/ every minute/ every meter etc.
If variable expresses something that is discrete like days, weeks and months, steps, etc
1おきに will mean “every second day, week, month”
●1。。。。。●2。。。。。●3
This expresses continuous variable, let’s say hours.
Black dots express hours, but between them we have minutes.
So the interval of one hour means 60 minutes. White dots express 10 minutes.
So after an interval of 60 minutes, we have the next event at 2 o’clock.
So you can say that the event happens every hour (at 1st o’clock, 2nd o’clock etc).
That’s why 1おきに can be swapped with 1ごとに for those.
For discrete variables the situation is different.
Let’s say our variable are days. We assume that day cannot be split.
1 - Monday
2 - Tuesday
3 - Wednesday
4 - Thursday
5 - Friday
①②③④⑤
The event will happen with an interval of one day.
Black dot expresses the interval.
①●③●⑤
So the event happens on Monday, and Friday.
So we can say it happens every other (second) day.
That’s why １おきに cannot be swapped with 1ごとに、but with ２ごとに。
Is it more clear now?
Hi
Thank you very much for your very detailed explanation. I understand it better now but there is just one thing that I still don’t understand - what does ‘descrete’ mean in this situation and why is a hour considered as ‘continuous’ but a day is not? Surely days, months, years, etc. are just as continuous as seconds? Or am I just being stupid? 
Good point dear sir,
Basically, we assume that there is no such a thing as half Tuesday, half of a step etc because noone really says that.
Thanks! Yes that’s 100% clear now although that different way of thinking will take a bit of getting used to. I’ll try using it as often as I can.
hi, i think i understand the usage of this construction, but what if I actually want to say "every other hour (or any continuous variable)? what construction do i use then?
Wouldn’t you say ２時間おきに in this context? Maybe?
@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!
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?
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:
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!
I want to suggest a link. The pictures here were really useful to me.
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.”
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!
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.
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.
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.