Nishi-no-Mon Yoshinoya is a sake brewery just west of Zenkō-ji, making it an easy cultural stop while visiting Nagano's most important temple. The brewery setting adds a taste of local craft to a district otherwise dominated by temple approaches and souvenir shops.
It is not a large museum, so come for a short look, tasting or shop visit rather than a deep tour. Its convenience near Zenkō-ji is the main advantage, especially if you want a locally rooted break after the temple precinct.