Etymology and distribution of 古坂.

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
↑オフライン検索できるアプリもどうぞ
在日通名大全

日本初、在日通名の研究書「在日通名大全」発売中!
ネットの電話帳 住宅地図 マッポン!

「古坂」さんの名字の分布数。

カンマ区切りで複数の名字を指定できます。

Etymology of 古坂

Distribution of 古坂
Ranking
1 Aomori-ken(About 300)
2 Hokkaidou(About 100)
3 Nagano-ken(About 100)
4 Ishikawa-ken(About 90)
5 Chiba-ken(About 80)
6 Hyougo-ken(About 70)
7 Kanagawa-ken(About 60)
7 Toukyou-to(About 60)
9 Saitama-ken(About 50)
10 Oosaka-fu(About 40)
10 Kyouto-fu(About 40)
12 Ibaraki-ken(About 20)
12 Ehime-ken(About 20)
14 Fukui-ken(About 20)
14 Nara-ken(About 20)
16 Shiga-ken(About 10)
16 Hiroshima-ken(About 10)
16 Gifu-ken(About 10)
16 Miyagi-ken(About 10)
20 Aichi-ken(About 10)
21 Shizuoka-ken(Very rare)
21 Akita-ken(Very rare)
21 Fukuoka-ken(Very rare)
21 Niigata-ken(Very rare)
21 Shimane-ken(Very rare)
21 Iwate-ken(Very rare)
21 Wakayama-ken(Very rare)
21 Mie-ken(Very rare)