This ineffable teaching is very new in the West. Why would we not get all the guidance we can?
Since the whole universe is an experiment in learning, it’s good for a teacher to continue their own training. Whatever efforts they put into it will be in service of their students, and will directly benefit them. If the teacher is still in a relationship with a master of their own that requires some humility, well and good. They will also still be subject to some accountability.
In the case of koan training in Zen there is even more benefit. This ineffable teaching is very new in the West. Why would we not get all the guidance we can?
And yet it’s actually easy to see why. One of the hazards of koan training is that it may open us to experiences that seem complete and whole, lacking nothing. Any time someone has a taste of “kensho,” it appears – and is – complete, universal. There could be nothing more, and nothing is left out. It’s hard to imagine there could be different levels and depths of kensho.
Only a master who has undergone long training will be able to gauge the depth of a student’s experiences. In fact there are many nuances. The koans are not merely “brickbats,” as Mumon said. They have great subtlety too, and ever-increasing beauty. Wouldn’t it be wise to max out on the deeper guidance available to us while we can, from the culture that has been nurtured by them the most, namely Japan?