This is from the final game of BO5 for the Japanese Jundan title match today (April 28, 2026)
Shinbano plays a very rare response to Shusaku’s kosumi. And I believe I saw patterns similar to this before, but not in the context of Shusaku’s kosumi. Instead, it was in the era of high/low Chinese, when there is a stone at the high/low Chinese location, or with a 3-space low/high pincer, and the opponent did a three-space high jump in response. One of the refutations is to play the kosumi to threaten the 3-space high jump.
This is equvalent to that pattern without the side stone, and tenuki after the 3-space jump, inviting the split. For this to work, either you already have an outside influence, and the stone can run on the side, and not be afraid of getting split (since it is not countering the high/low side/pincer stone).