Japan for 90 days to Korea to Japan to US

Hello! I am going to be studying abroad in Japan for 87 days this summer. Because it is under 90 days, I will not be getting and cannot get a student visa. However, I wanted to stay a week or two after my school ended to explore more while I am in Japan. I have heard some people say they went to Korea for a week and then re-entered Japan. Does any have experience or tips for this? Is this technically legal?

If I do this, would I have to buy a plane ticket that departs from the US and goes to Japan and then have the �greturn�h flight go to Korea? And then buy a ticket from Korea to Japan and Japan to America? I was thinking I can�ft buy a ticket from America to Japan to America that is over a 90 day visit even if I go to Korea in the middle.

Thank you advance!!

You just need to leave Japan for one calender day. Country doesn't matter.

Totally legal
Many people do this
A day outside is enough but if you have time, sure why but visit Korea or Taiwan
Upon recently you�fll get a new 90 tourist �gvisa�h

@LikeBike

But after the second 3 months, they can't come back for 6 months, correct?

@Denis C
Sorry not sure what you mean. But you can come more than 180 days a year to Japan on a tourist visa.
However OP wants 87 days plus ~ a week. No problem with that.

To board the flight to Japan the OP needs an onward ticket - their trip to Korea satisfies that requirement. Staying 87 days and then departing is fine.
On return to Japan (again with your onward ticket), you get another temporary visitor permit.
But after the second 3 months, they can't come back for 6 months, correct?
Not correct, you can visit as many times as you like with cumulative duration of almost a year as long as you stay under the 90-day limit (actually 91 days as the first day is counted as a day zero). I have personally exceeded well over 200 days in a single 365 day period before I moved to Japan. Made me tax resident in Japan as a result.

So you can basically move to Japan indefinitely to an extent, as long as you leave for at least a day, every 90 days?
Seriously?

@Denis C - not quite as simple as that as you run into other complications, but in essence, yes.
Complications can include things like not being able to get a bank account, local phone, driving (after one year), health coverage and tax issues/double taxation.

Plus you can�ft work. So unless you are rich you�fd run out of money at some point.

Well, you can work, but not in Japan (i.e. for a Japanese company). You can work for an overseas business. The temporary visitor permit is not just a "tourist visa".
Even the new digital nomad visa is pretty limiting and certainly not a good solution for staying in the country.

Thanks a lot, I understand about the complications in staying like that but I thought tourist visas were more limited.
It's of interest to me as I am very interested in retiring (partially probably) to Japan when that day comes and this situation makes it much easier to "try out".

Well off the OP's original topic, but Japan isn't really a retirement destination country. I suppose if you are seriously wealthy it might work.

they can change their policy at any time.
at present it works, no one knows the future.
the typical example is that Japanese government will introduce the new policy that the permanent resident status may be cancelled when they don't pay tax, pension, health insurance, etc.
that is, the government chooses foreigners. (or in another word, because there are so many bad foreigners in Japan. they need to make such decisions.)

I'm confused, this thread contradicts this one https://www.japan-guide.com/forum/quereadisplay.html?0+179131

Who is right?

How are the two threads contradicting each other?
In the end, the OP of the other thread confirmed that his GF managed to do 3x 90 days (more or less) consecutively in Japan, which corroborates what LikeBike and JapanCustomTours say here.

The only "contradiction" with that other thread is the incorrect information in one of the early posts.

There were 2 posts, not 1 contradicting but if they're incorrect then great.
I hope to have the opportunity to make use of multiple consecutive stays.