As of the close of business on December 30, 2019, Japan Post Bank (Yu-cho Bank – JPゆうちょ銀行) will no longer issue International Postal Money Orders. After this date, it will not be possible to purchase money orders for mail-in passport renewals in Japan.
That was sent out by the U.S. Embassy, but I am guessing that applies to all passport holders of many other nations.
The search tool here did not show any hits when I used it, so if I have erred and have repeated a post already done, my apologies to management.