Is it illegal for three online mahjong games not to draw water 100 games to win or lose?

Illegal. It is not illegal to gather people to play mahjong online if it is just for entertainment, but it is illegal if it is suspected of gambling. According to Article 70 of the Law on Public Security Administration Punishment, anyone who provides conditions for gambling for the purpose of making profits, or participates in gambling in a large amount, shall be detained for not more than five days or fined not more than 500 yuan.