I'd agree with you, accept there's this:You can do something without knowing what it's called.
Even if we accept that a) no one else has ever mentioned this apparently common practice in front of him before and b) none of the people he has done it with have ever mentioned it before, the author is telling us that his master literally told him what to do and who he should do it with without ever mentioning it by name? I don't think that really makes sense. Not a big deal, but I thought it was funny. Kind of like one of those "as you know..." scenes.