Ussuri Brown Bear
The Ussuri brown bear (Ursus arctos lasiotus) is only found in Hokkaido in Japan, though it can also be seen in areas of Russia, China and Korea. Adults in Japan can weigh more than 400 kilograms (880 lbs), though they more typically range from 150 to 250 kilograms (330-550 lbs). Their diet comprises insects, birds, fish and mammals, though they will also eat crops.
Brown bears in Hokkaido have been known to attack humans, so it's very important to keep on guard, take preventative measures and be prepared in case you do have a bear encounter. Hiking in a group and making noise tends to encourage bears to keep away.
Asian Black Bear
Though much smaller than brown bears and typically weighing only 60 to 200 kilograms (130-440 lbs), Asian black bears (Ursus thibetanus) are more aggressive toward humans. In Japan they're found in Honshu and Shikoku and are not only confined to deep forests and are also occasionally found roaming the streets of towns and cities near forests.
The white patch on its chest makes it easy to identify, but make sure you don't run when you see one—it'll chase you down! Your best bet is to slowly back away quietly without turning your back on the bear.