[animal_spirits]

Another comment here referenced the Ise Grand Shrine [0], so that is what I bet the OP is referring to. I pose this, religion isn't only about spiritual beliefs, it encompasses rituals, culture, and history. Knowledge transfer is a major part of continuing a religious culture, whether it be through studying of scripts or preaching. So, just because it is religious based doesn't exclude it from also being about transferring of knowledge.

[0] https://en.wikipedia.org/wiki/Ise_Grand_Shrine

[mutatio]

The link provided shows that it is due to the religious belief of rebirth, the tradesmen themselves practice their skills continually, so the theory still doesn't map for me. Moreso if we apply Occam's razor: there's no evidence the Japanese practice is for skill transfer yet it's being used to promote that premise for something else.