Etymology and distribution of 古太刀.

Kotachi 【古太刀】^{レベル2
About 20}  The Japanese surnames etymology dictionary.

Toukyou-to , Kagoshima-ken .

① Toukyou-to Akiruno-shi It was in Ninomiya during the Edo period.

② Topography . "Hara" was added to the quietness which is the surname of Amagi archipelago of Kagoshima-ken . There was a case where Oosaka-fu changed name from surname in 1950. 静 Shizuka reference.