If you are visiting Nagano, this is one of the most beautiful winery to visit.
Walking through the vineyard and you will reach the beautiful main building of this winery. (Actually, this is my favorite!)
The quality of wine is almost fine although still has the potential to improve; but you can enjoy unique wine made from Japanese (especially Nagano's) indigenous grape, Ryugan along with international grapes. They also have regular winery tour you can attend without reservation for free (Japanese language only).
There is a fine restaurant where you can enjoy beautiful scenery, while if you like a casual meal, you can order their hand made sausages (shown in the picture) or whatever you like from their deli, and enjoy them in the beautiful garden where a various events are frequently held especially in the weekends.
They also proud of many food products such as jam, cookies, honey etc. So you can enjoy your shopping, too.