2007 Korean Baduk League, Song Taekon - Na Jonghoon

This position from game after 186 move between Song Taekon(8p), Team Hangame and Na Jonghoon(6p), Team Ulsan Diachae, in 2007 Korean Baduk League. Next move - tesuji black.
On left diagram after 7 move, white need "А". The next position is clear - white lost 6 stones. On right diagram, after 5 move became "ko".
But in that moment white lost is bigger if connect. If atari on selected stone, this variant white end in gote. In any case black must play this variant.

Song Taekon(8p), Team Hangame - Na Jonghoon(6p), Team Ulsan Diachae - B+10.5