The Yamanashi Prefectural Museum has a large exhibit covering the history of Yamanashi and also some rotating exhibitions on art and other subjects that generally relate to Japan.
The museum's main exhibit, encompassing aspects of Jamon culture and life in Yamanashi many years ago, is very child-friendly and has many English translations. There are many creatively-designed exhibits which encourage participation. These are especially exciting for children.
The museum also has rotating exhibitions, which will appeal more towards adults. The last exhibition was on Buddhist art, which many sculptures and scrolls on loan from local temples. I particularly enjoyed the work from this exhibit but there was no information in English available and the guides' English was practically nonexistent.
The museum has a garden area around the museum. There are benches set up for those who may want a picnic. The museum also has a gift shop and cafe.
The museum is usually open from 9:30am to 5pm and closed on holidays and any day after a holiday. The admission for the permanent exhibition is 500 yen but there are discounts available for students. Local buses run to the museum regularly. Parking is readily available. There is a little bit of information in English at www.yamanashi-kankou.jp/english but the museum's official website at www.museum.pref.yamanashi.jp only has Japanese.