"Gyuhi" is used for Japanese sweets such as "Daiku".
Please go to the Japanese sweets shop.
Japanese sweets shop is also located at souvenir department of Tokyo station.
Most of "Anmitsu" includes gyuhi in it. Anmitsu is like a parfait contains red beans, shiratama dango, kanten, ice cream, gyuhi, and some fruits. You pour black (or sometimes white) sugar syrup to add flavor. There are many famous cafes to try Anmitsu in Tokyo.
For example, Kanoko in Ginza, Umezono in Asakua, and Hatsune in Ningyocho.