Mp3tag shows Korean, Japan etc language texts as squares

Mp3tag shows Korean, Japan etc language texts as squares while I can see these tags with Jaikoz or Picard correctly. I tried utf-16 and utf-8 settings but no help.

If you use MP3tag under Win XP then this is a system deficiency as XP does not have the right font.
All later OS should show the characters correctly.

But then how Jaikoz and Picard shows such langs?

You asked about MP3tag - this is the explanation. (BTW: ICQ does not show these characters either ... )
Switch to an OS that does reach its end of life in early 2014 and you have it.

There's still one year and millions of active Xp users. If Picard can do then why not Mp3Tag support it?

You can install East Asian language support from the Regional and Language Options in the Control Panel to get unicode characters working.