A short trip from Tokyo is Suwa in Nagano. The city of about 50,000 people sits on the shore of lake Suwa and has mountains nearby. We love coming here as it is one train from Tokyo, as the air is refreshing, and Nagano is known for good sake and food, particularly soba.
We are big fans of Masumi sake, which has a lovely tasting room in Suwa. Nearby are four other sake breweries with tasting rooms worth visiting. You can make an afternoon of tasting and exploring sake. Then spend the rest of the day soaking in an onsen hot spring and dining in a ryokan.
Here are the five breweries, all within a few minutes of each other, and walking distance from the city center.
Maihime 舞姫
Nagano-ken, Suwa-shi, Suwa 2-9-25 長野県諏訪市諏訪2-9-25
Reijin 麗人
Nagano-ken, Suwa-shi, Suwa 2-9-21 長野県諏訪市諏訪2-9-21
Honkin 本金
Nagano-ken, Suwa-shi, Suwa 2-8-21 長野県諏訪市諏訪2-8-21
Yokobue 横笛
Nagano-ken, Suwa-shi, Suwa 2-3-6 長野県諏訪市諏訪2-3-6
Masumi Miyasaka Brewing Company 真澄 宮坂酒造
Nagano-ken, Suwa-shi, Motomachi 1-16 長野県諏訪市元町1-16
https://foodsaketokyo.com/2016/09/29/nagano-masumi/
More information on Suwa City in Nagano in English:
http://en.go-centraljapan.jp/lsc/lsc-upfile/pamphlet/01/40/140_1_file.pdf
More information on sake breweries in Nagano:
http://www.japansake.or.jp/sake/english/kuramoto_map/nagano/
Food Sake Tokyo 
Sounds like a great place to visit! I can’t wait to get back to Japan for a longer stay.
I hope your travels bring you back, soon! Arigato, Yukari
Hi, I’m planning to go to Lake Suwa for an overnight ryokan stay from Tokyo. Is this enough time to cover the sake breweries, castle and shrine assuming I arrive at Kamisuwa about 10am and I leave in the afternoon the next day?
Yes, that is plenty of time to see the sake breweries. I didn’t visit the castle and shrine, so you’ll need to research how much time you need for that. I hope you have a delicious time in Japan!