Chocolate factories in Japan

I'm planning to visit Japan this September.I'd like to visit a chocolate factory and the chocolate-producing process. Except the factory in Hokkaido, are there any other factories offering visits and where are they? thank you so much.

There seems to be a Lloyd's Chocolate World on the third floor of the New Chitose Airport.
http://www.royce.com/contents/english_rcw/

The Glico factory is in Kobe.

Meiji's Saitama factory is chocolate-focused.

Lotte also has one in Saitama.

Ishiya Chocolate Factory makes Shiroi Koibito cookies and they're famous in Sapporo. I was given a personal tour by the owner of the factory, who also owns the Condasole Sapporo Football Club, along with her friend and it was quite fun. It was like Willy Wonka meets Disneyland. There's also quite a collection of different items the original owner collected during his life, like anime figures, phonographs, whatever. It was worth the time.