JCB credit card in Japan

I live in Hawaii, specifically Oahu, land of signs often in both English and Japanese because of the number of Japanese tourists. I recently got a JCB card. I'm going to Japan in May and plan to take plenty of yen, but I hope to use this at places that actually accept it (I know my hotel does) so I can save my yen for cash only places.

I plan to only be in the Tokyo area for the entire trip. What kinds of places might accept my card? Will department stores take it? Any other places? I'm well aware restaurants are going to likely be cash only.

I've used my Mastercard at some of the following places:

Many family restaurant chains
Larger supermarket chains (eg Tokyu, Seijyou-Ishii, Ito Yokado, etc)
Department Stores
Disneyland Resort
To buy Shinkansen and Long Range train tickets @ the JR Ticket Counter. (not the machines)

Not accepted at most:
Convenience Stores
Fast Food Restaurants
"Mom & Pop" Restaurants and Stores

The JCB card is a Japanese card company. Any place in Japan that takes credit cards is most likely to take the JCB card.

The question is more to do with, what places take credit cards.

Well, many places take credit cards and many places do not.

Most supermarkets take credit cards, larger restaurants will take credit cards (look for signs or ask), many taxi's take credit cards, hotels of course take cards, some convenience stores like LAWSON take credit cards, other convenience stores do not. Most department stores will take credit I know that for sure. I don't know of a department store that doesn't take credit or offer their own credit card.

Pretty much it just depends on the particular establishments. For example I found some 100yen shops do take cards at special designated counters, while other 100yen shops do not take credit cards.

When in doubt just look for the signs.
As always have cash backup for small things in case.

Many restaurants take credit cards, but if it is a hole in the wall noodle shop it won't. It isn't common practice in Japan yet to use a credit card for small purchases, but departament stores will certainly take your JCB card.