There are several Japanese potato chips manufacturers but the Japanese market is dominated by Calbee which has more than 60% share of potato chips market.
Then, the flavors are different than in Europe. The popular flavors are slightly salted and seaweed & salt. Then, there are also spicy flavors including extremely spicy ones.
Europeans use there fingers to eat potato chips but there are some Japanese, especially young ones who use chopsticks when eating potato chips. The reason is not due to hygiene but not to make dirty their PCs or smartphones.