The tiebreaker EXT stands for Exploits Tentes (difficulty faced). Its idea is to measure the difficulty of the games played by one player. It is used in OpenGotha
We take AH, the actual number of handicap stones used. We take NH, the natural number of handicap stones. Then we calculate the co-efficient (C) for each game via the following rules.
- if AH < NH then C = 0
- if AH = NH then C = 1
- if AH = NH + 1 then C = 2
- if AH >= NH + 2 then C = 3
EXT is then the sum of: C times the SOS of the opponent.
See also EXR
The exact definition of AH is needed. I imagine that by default if a 3kyu plays a 4kyu, then AH has the value of 1.
Each SOS is the score at tournament end.