Etymology and distribution of 五百.

Iho 【五百】^{レベル2
About 30}  The Japanese surnames etymology dictionary.

Fukuoka-ken · Gifu-ken . 岩佐 's variant. In Fukuoka - ken tells that Iwasa 's surname and Yuasa' s surname are misleading because they are renamed. Estimated from tradition around 1900. 岩佐 Iwasa reference. 湯浅 Yuasa reference.