The taisha jōseki (大斜定石) is the Japanese term for the most celebrated of all joseki (standardized sequences) in the game of go.
For several decades, although the complicated variations may have been known and privately studied, they hardly appeared in important games.
(Since the taisha formation can also occur when White has a pincer in place, on the top side of the board in the diagram, it would have been studied also in that context.)
These depend on external factors (the available ladder tactics) and can in some cases lead to difficult ko fights and capturing races.
Therefore White's resort to trying to cut across Black is often forced, in effect, by the wish not to submit and play passively.