The received file (/usr/kde/3.5/share/apps/libkholidays/holiday_ja) encoding is EUC-JP. Characters of holiday names on Korganizer became garbled. When trying to change the file encoding type to UTF-8, this problem was solved.
Please, report this upstream (http://bugs.kde.org/)
I reported to bugs.kde.org http://bugs.kde.org/show_bug.cgi?id=140060