The temple grounds were rather deceptive in their structure. Of course, the tallest building was something you could see for miles off, but you would assume that was it. The mountain was only small, after all. But under the cover of trees, centuries of monks had cultivated quite the environment for training.
And with training as their objective, one of the most important things for them to measure was progress. And the best way to do that, was through rigorous testings in the form of combat. One found out very early on which of their peers they were most similar to in terms of ability, and they would spar endlessly, until one left the other behind.
As the monks grew older, the duels grew more and more complicated, with the new techniques that each had learned. It was more akin to a chess match when the opponents were evenly matched. Thus, the younger monks often gathered, so that they might learn from their elders, and improve their own training.