Niigata is in the Chubu region, located along the coast of Japan Sea. It is famous for rice, Nihonshu, more commonly known as 'sake' and skiing.
Saga is a small prefecture in northern Kyushu. Compared to other prefectures, Saga seems to have little to offer. Even the locals make fun of it by creating songs on that.
Fukui prefecture is a relatively small one along the Sea of Japan, in the Chubu Region. It has few attractions, the most famous ones being Eiheiji and Tojinbo, rugged cliffs with big waves.
Aomori is the northern most prefecture in Honshu , and just below Hokkaido in the Tohoku region. It is famous for apples, Hirosaki Castle and Osorezan. Out of about 30 sakura spots I have visited in Japan, Hirosaki Castle win the others hands down. Osorezan Fear Mountain is 1 of the 3 most sacred spots in Japan, and its vibe and landscape is really exceptional (I have not come across another place like this in Japan). Thanks to these 2 incomparable attractions, Aomori has become one of my favorite prefectures in Japan that I'd highly recommend.
Aichi is the prefecture for Nagoya, Japan's 4th largest city. Nagoya is a good base for travelling around the Chubu region, such as to places like Takayama, Shirakawa-go, Gero Onsen, Inuyama, KisoValleyetc, and also to Nagashima Resort and Ise Shrine in Mie prefecture to its west.
Ehime means "lovely princess" and is located at the north-western part of Shikoku. It is famous for 1 of the oldest hot springs in Japan-- Dogo Onsen, and Imabari towels, THE name for good-quality towels. It also has 2 out of 12 original castles in Japan-- Matsuyama-jo and Uwajima-jo. Being a fan of onsen and castle towns, this prefecture is of course not to be missed!
Nara was the first capital of Japan. It is located in the Kansai Region, less than 1 hour train ride from Kyoto or Osaka. It gives off the same vibe as Kyoto as there are many grand and ancient temples and shrines. And it is famous for free roaming deers, just like in Miyajima and Yakushima.