Tewari

Tewari is a Go concept used to analyze sequences of moves by breaking them down and rearranging or eliminating them to evaluate their efficiency. The term tewari literally means “hand division” and is believed to have originated in Japan in the late 1600s. 

There are two primary ways to apply tewari:

1. Reduction comparison — Remove an equal number of stones from both players in a local position and assess the remaining structure. This helps determine whether the earlier stones contributed meaningfully or were inefficient.
2. Order inversion — Rearranging the sequence of moves to see if the same result could be achieved more efficiently. If a different move order produces a better outcome, it may indicate that the original sequence was flawed.

Tewari is most useful after a local situation has settled, as it requires a stable position to draw meaningful conclusions.