A welcome bonus is a bonus that a casino offers its players once they join their site. It's a way to appreciate new customers and encourage them to play. However, any winnings from the welcome bonus may have to be used to make other bets before any withdrawals can be made.
When mentioning Japan, people often think about sushi and samurai, but the Japanese are also famous for being hardworking and humble. Most forms of gambling are banned in Japan, but online mobile gambling is growing fast in the country and it's easy to find attractive bonus offers targeting Japanese residents.