3rd Prices Information Cup, League D, Rui Naiwei - Choi Wonyong

This position from game between Rui Naiwei, 9р, and Choi Wonyong, 5p, from 3rd Prices Information Cup. The next sequence is classic tesuji from gandicap game.
After that moves black successfully outgoing in center.
After 17 move, black can connect two stones, but in real game Rui Naiwei select to attack white stones on left side. The main idea was - create territory on lower side and in centre.

Rui Naiwei(9p) - Choi Wonyong(5p) - W+4.5

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