I don't know the name, but it is from 1975, and it is been made for the Expo in Okinawa. It has number 100 in the middle. Fare condition.
to Cointalk Simon. Y#85, a ¥100 cu-ni coin, had a mintage of 120-million to commemorate the Showa 50 (1975) International Ocean Exposition, held in Motobu Township, Okinawa . The 2007 34th Ed. Standard Catalog of World Coins gives values of $1.75 VF, $2.50 XF and $3.50 Unc. All of those valuations are on the high side IMHO, and the Japanese Numismatic Dealer's Association 2006 catalog value for the equivalent of AU-Unc. - ¥200-250 (~$1.70-2.15) - is much more realistic. Without seeing a picture, there's no way to guess what grade your "excellent condition" equates to.
