Back in one of the old Chinese dynasties the towns had gongs that would be rung each two hours: At 8am once, 10am twice, noon thrice, 2pm four times, etc.

The lawyers of the day would stretch out the trials as much they could to make more money.

But the judges became extremely bored with the status quo and went to the emperor, getting a proclamation that all trials would have to be concluded at 2pm.

Thereafter all trials ended with a four-gong conclusion.