I’m always happy when I get a cover form Japan. All the ones I have received so far were clean with a very neat postmark. Another thing is that, even if they came from various expeditors, they were almost all franked with prefecture stamps. Prefecture stamps are stamps sold locally to a prefecture but that can be used in the whole country. The last cover I got is not different.
The stamp on the left is a definitive stamp. It belongs to a series about fauna and flora started in 1992. This specific stamp was issued on the 28th of November 1997. Thank to Eric, I discovered this website about prefecture stamps from Japan. This helped me to confirm that the two other stamps are prefecture stamps (this can bee seen from the shape of the kanji used to write the country name). I also could find out that these stamps are from the prefecture of Yamanashi. They have been issued on the 2nd of July 2001. The one in the middle pictures horses and the Mt Yatsugatake highlands. The one of the right pictures Oshino-hakkai ponds. Just for the pleasure, here is the full set.