If you are stuck in the Yamanashi area and cannot find a hotel or don't want to spend too much on accommodation, why not stay overnight at this 24-hour onsen called Kaisen Healing Resort Spa. This onsen is famous for its power stones that have a healing effect. The women's outdoor bath has huge pink quartz stones and is illuminated at night.
Pay only 2,200 yen and you can stay for 24 hours. Children 3 years old and above pay 1,100 yen while children 2 years old and below are free. The fee includes towel rental, yukata, bathing fee, and use of sleeping rooms, sauna and "ganbanyoko". You don't have to bring your own toiletries.
Try the "ganbanyoko" or hot stone spa to relax or take a nap...if you can take the heat. Unlike other resort spas, you don't have to pay an extra fee to use the "ganbanyoko". Other amenities include free WIFi, a restaurant, a library, and a nice garden area. You can also ask the front desk for free use of playing cards and board games like Shogi, Go, Othello, Uno and Jenga.
If you are planning to stay overnight, there is a tatami floored relax-area. Mats and wooden pillows are available to use after 9 pm. Alternatively, you can go to the first-floor break rooms with reclining chairs equipped with a TV, or go to the mezzanine and sleep comfortably on a bed with side panels for privacy.
If you like this resort spa and think you'll go back again, better get a member's card. It's free of charge. With the membership card, adults pay only 1,800 yen and it's 980 yen for kids. Not only that, during your birth month, you can enter for free once and get 10% to 15% on massage services and "akasuri". Plus you get a free dessert at the restaurant.