The Chinese Super League (CSL) is one of the most popular football leagues in China, and it has its own set of rules for player appearances. One of these rules is the U23 player appearance rule.

According to the rule, players under the age of 23 must play at least three matches per season before they can be eligible to join the senior team. This rule was introduced in 2017 to promote youth development in Chinese football and prevent clubs from using young players as bargaining chips.

In order to meet this requirement, clubs must ensure that their U23 players have enough playing time on the field. This means that they should be regularly involved in training sessions and games, and they should also be given opportunities to start matches.

However, there have been criticisms about the implementation of this rule. Some argue that the U23 players may not receive sufficient playing time, which could lead to them becoming less competitive with the senior team. Others believe that the rule may create a "double-standard" situation, where players who are older or more experienced than the U23 players may still be able to compete against them.

Despite these criticisms, the U23 player appearance rule remains an important part of the Chinese football system. It helps to promote youth development and ensures that the best talent is given a chance to shine. However, it's up to the clubs and the league to ensure that the rule is implemented fairly and effectively.