Etymology and distribution of 古柳.

The Japanese surnames etymology dictionary.
https://play.google.com/store/apps/details?id=info.jigensha.jcedfreeGoogle Play で手に入れよう https://apps.apple.com/us/app/id1471109324
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Popuration of 古柳.

カンマ区切りで複数の名字を指定できます。

Etymology of 古柳

Distribution of 古柳
Ranking
1 Shizuoka-ken(About 20)
2 Fukuoka-ken(About 10)
3 Mie-ken(About 10)
3 Oosaka-fu(About 10)
5 Chiba-ken(Very rare)
5 Yamaguchi-ken(Very rare)
5 Shimane-ken(Very rare)
5 Hiroshima-ken(Very rare)
5 Aichi-ken(Very rare)
5 Okinawa-ken(Very rare)
5 Kanagawa-ken(Very rare)