This is a popular backpackers' spot with all the fixings: friendly, bilingual staff, clean rooms with modern bunks, private lockers, free coffee and tea, no curfew, laundry facilities, a kitchen and a communal lounge space. Bonus: the owner is a juggler and the hostel doubles as a shop for juggling goods.
From the subway exit (don't go to JR Shiroishi Station!), walk straight for a few minutes along the main street in the direction of the Eneos petrol station. Turn right at the fourth traffic light and you'll see a detached two-storey white building – you've arrived! The English website tells you all you need to know.