Raindrop cake is a water confectionery made from the famous water of Hakushu Town, which is underground water in the Southern Alps, and hardened to the last minute to retain its shape. It was released last summer and gained popularity, and it seems that it has been sold again this year.
It's so soft that it's almost bursting just by poking it, and when you put it in your mouth, it turns into water that disappears.
If you take it out of the bowl and expose it to room temperature, it will lose its deliciousness in about 30 minutes, so it will be sold only at stores (reservations and take-out are not possible). There are two stores, the Daigahara store and the Nirasaki store.