I've been doing some reading of the PDF at https://www.dic.go.jp/english/, in order to understand how protected deposits are in Japanese banks.
My current understanding is this:
Deposits that do not earn interest are 100% insured.
Deposits that earn interest are insured up to 10M yen per financial institution. Anything more than that, you get whatever comes out of the bankruptcy process.
Foreign currency deposits, and deposits at Japanese-based branches of foreign banks are not insured. You get whatever's left if the bank goes under.
All Japan Post deposits are 100% guaranteed by the government.
Conclusions:
If putting more than 10M in cash in yen a Japanese bank, make sure it earns no interest, or spread it between financial institutions. Less than 10M is fine.
Don't keep a significant amount of cash in foreign currency deposits, or Japanese branches of foreign banks.
If you want a cast-iron guarantee, use Japan Post.
I'm not sure about the whether earning no interest is the criteria for whether insurance is capped at 10M, or whether it's the category of account. Anyway, it's definitely worth thinking about if you're ever in the position of depositing a large amount of money. I think the lack of insurance on foreign currency deposits could be news to some people here.
Yep, the lack of foreign currency protection is good info. I am intending to open a Sony account soon partly because I like the idea of being able to buy foreign currency for future overseas travel (whenever that may be...), but will be sure not to keep much in foreign currency.
On the 10m thing, I had to keep over that for a while after sending cash here for a house purchase, and being of a paranoid bent (and a former Icesave customer), I was fully prepared to open a second account at a different institution, but my current bank changed it over into a non interest account instead and indeed assured me it was protected. There was a name for the specific type of account, which I thought was ‘teiki’ but that seems to mean term deposit so can’t be that. It was a simple enough process.
Thank you for the information, very useful. Foreign currency deposits seems to get quite be pushed by banks, so I wonder if the lack of insurance is another reason for that.
All Japan Post deposits are 100% guaranteed by the government.
Can you mention the source for this? Most of what I have seen seems to suggest that ゆうちょ accounts have the same upper limit as most banks.
From the PDF I mentioned in the first sentence, box at the bottom of page 3. However, it's pretty old and you could be right. The Yucho Bank page you linked to on the other thread seems to imply otherwise, but it's unclear. Would be nice to get a definitive answer - no time to look into it further for now.