Tofu is cheap and sold everywhere in Japan, but the packs look alike. 木綿 is firm, 絹ごし is silken, and 厚揚げ is thick fried tofu.
木綿豆腐
momen dōfu · firm
絹ごし豆腐
kinugoshi dōfu · silken
厚揚げ
atsuage · fried, holds its shape
In the shop
Chilled case, with natto and konnyaku.
Which shops
Every supermarket and convenience store. 3-packs of small blocks are the cheapest.
Watch out
For stir-fries, mapo tofu with chunks, or grilling, take 木綿. 絹ごし falls apart unless you only simmer it gently.
Lazy Recipe sees that you're in Japan and turns any dish into 3 steps with what Japanese supermarkets sell. Your shopping list shows each item's Japanese label and aisle.