Don't peep at bamboo joints
This saying is likely a mistaken impression for a proverb that says not to peep on both sides of a bamboo joint. " 竹節の両ﾉｿﾞｷするべからず " 両ﾉｿﾞｷ means double peep. I. e., White should avoid this shape if at all possible.
Here, throws itself against a wall. This is worse, because it loses a liberty immediately, but the idea is more or less the same: a bamboo joint is almost as strongly connected.
The proverb in fact warns against moves that are not peeps at bamboos as such, but will inevitably become if you read a little further. In particular peeping at both sides of the bamboo must be avoided. Here is a nice illustration of this proverb:
White here is called a trick play in a Korean book. That seems unfair. But the point is that Black might play at a in answer. Then after to , Black would be peeping at both sides of a bamboo joint, which is taboo. One peep may be acceptable, but with stones at and a it can't be that both are efficient.