3-5 point low approach one-space low pincer, tenuki
Here it is generally a bad idea for White to ignore the pincer . When Black plays there is too little aji left to work with in the corner. Probably the position after is better for Black than if White had simply allowed Black to enclose the corner at ; while the local tally is the same.
This position from an Oteai game 1970-04-22 developed from a Shusaku fuseki-style side at . The tenuki play was matched by to attack White's shape. See Avalanche - connection for the sequence on the left.
As the game progressed, the gain from is balanced by Black's bending back of White with .
Since there was no komi, White may have felt that complex trade-offs were required.