Maguro まぐろ 鮪(tuna) is one of the most common sushi items and I love it very much. In Japan, it is appreciated not only as sushi nigiri but as sashimi, chirashizushi, donburi (for example, kaisendon 海鮮丼, tekkadon 鉄火丼) & onigiri おにぎり (for example, tuna-mayo ツナマヨ tuna & mayonnaise).
In Yamanashi, there are a lot of fine dining and belt-conveyor sushi restaurants. Though Yamanashi pref. holds no ocean coast, the prefectural capital, Kōfu, is No.1 city in Japanese prefectural capitals in terms of the average annual amount, per household, of maguro that had been purchased (2003-05), according to Yomiuri Shinbun Newspaper. That reminds me, my grandpa & grandma also used to eat maguro sashimi very often.
Please come to Yamanashi to eat good maguro dishes.