In one Japanese region they are singing Croatian old hymns:
Japanese preforming it:
U boj, U boj – 1000 Japanese singing
Nikola Šubić Zrinski – opera
As far as i know, there was a Croatian ship wrecking somewhere in Japan in early 1900's. Our sailors learned Japanes few of our national songs, they liked them alot and today we have 1000 manned Japanes choirs singing them on Croatian The name of the song is "U boj, u boj, za dom" i.e. "In battle, in battle, for homeland"