Waterproof-breathable fabric is necessary (Gore-Tex is better)
Warm Clothing (Down or Fleece Jacket)
It’s necessary even in summer.
Mobile Phone
Mobile phone is essential to see the map, grasp current location and call for rescue. Be aware that there are many bad connection areas in mountains. Don’t overuse the mobile phone to save battery.
Guide Map
Guide Map is essential but there is no mountain guide map for foreigners in Japan. So please use this site and online map services.
Water Bag and Water
It’s not easy to get drinkable water in mountains. So it’s better to get water befor e climbing. Fortunately, most of tap water is drinkable in Japan.
Food
You can get food at a convenience store or supermarket. There are many convenience stores in Japan, but be careful as it is not in the mountains. If you go to outdoor shop or sports shop, you can buy food specialized for climbing or camp. Calorie Mate Block is a regular item. You can buy it at convenience stores.
Crampons
Crampon is not item used only for winter. Even in summer, there is residual snow on 3000 m class mountains in Honshu or more than 1500 m class mountains in Hokkaido. If you go there in summer, you should have 6-8 points simple crampons.
Sun Protection Gear
Insect Repellent
There are blood-sucking insects such as mosquito and black fly in Japanese forest.
Bear Bell
Forests in Honshu and Hokkaido are habitats of bears. Hokkaido is habitats of Brown bear which is very big. It’s better to attach bear bell with your backpack so as not to encounter the bear.
Camping Gear
Tent
Tent that can withstand rain and wind.
Sleeping Bag and Mat
Even in summer, you should have a high thermal insulation sleeping bag.
Cookers
Stove
You cannot bring fuel to airplane, so you have to buy it in Japan. Fuel cartridges of these manufacturers are available in Japan : Coleman, EPIgas, JETBOIL, MSR, Primus, Snow Peak, SOTO. (Boldface brands is especially easy to obtain.)