Superko
Superko rules prohibit recurrences of an earlier board position under certain circumstances. The recurrence of such positions could be caused by long cycles, such as triple ko, eternal life or round-robin ko. When such a position happens in a real game, the players either play out the superko, which results in a tie, or they avoid the superko in order to continue the game normally.
https://senseis.xmp.net/?Superko
This tag gives a hint.
Created by d4rkm4tter.
Other tags:
Diabolical, 2-1 point, Attack, Bamboo Joint, Belly Attachment Tesuji, Bent Four in the Corner, Bulky Five, Carpenter's Square, Clamp, Comb-Formation, Connect, Crane's Nest, Dame, Damezumari, Door Group, Double Atari, Double Ko, False Eye, Fuseki, Geta, Golden Chicken Standing on One Leg, Haengma, Hane, J-Group, Joseki, Ko, L+1 Group, L-Group, Ladder, Loose ladder, Miai, Monkey Jump, Moyo, Nakade, Nose Tesuji, Oiotoshi, Oshi-tsubushi, Patting the Raccoon's Belly, Placement, Rabbitty Six, Sabaki, Sacrifice, Seki, Semeai, Semeai Type 1, Semeai Type 2, Semeai Type 3, Semeai Type 4, Semeai Type 5, Semeai Type 6, Sente, Separate, Shimari, Snapback, Spiral Ladder, Squeeze , Superko, Symmetry, Tenuki, Throw-in, Tombstone, Tsumego, Under the Stones, Weak Carpenter's Square, Yose [Create new tag]