QnA forums are currently English only. They're actively answering account linking question in dedicated forums here.
https://social.technet.microsoft.com/Forums/ja-JP/home?category=Windows10ITPro
https://social.technet.microsoft.com/Forums/ja-JP/home?category=windowsserver
https://social.technet.microsoft.com/Forums/ja-JP/home?category=security
--please don't forget to Accept as answer if the reply is helpful--