In Swisses, the Sonneborn-Berger tie-breaks are not calculated correctly.
For example, see the player in 85th place in this tournament: lichess.org/swiss/ILOHq9MS
He has 2 points, and SB of 4. He played two games which should count towards the SB score:
Round 1: Full-point bye
Round 2: Win v player who scored 4 points
It seems as though the Round 2 game is the only score included in the SB calculation.
However, points should also be added for the Round 1 game. See 13.15.2 here: handbook.fide.com/files/handbook/C02Standards.pdf
"For tie-break purposes a player who has no opponent will be considered as having played against a virtual opponent who has the same number of points at the beginning of the round and who draws in all the following rounds. For the round itself the result by forfeit will be considered as a normal result. "
Therefore, in this case, the virtual opponent has 0 points before Round 1 (of course!), loses in Round 1 to the bye, and then in Rounds 3-6 is awarded the equivalent of a draw. So the Round 1 result is not just a full-point bye, but it for the purposes of SB calculation it the equivalent of a win against a player who scored 2.5 points. Therefore, this player's SB should have been 6.5.
13.15.3 is also relevant.
For example, see the player in 85th place in this tournament: lichess.org/swiss/ILOHq9MS
He has 2 points, and SB of 4. He played two games which should count towards the SB score:
Round 1: Full-point bye
Round 2: Win v player who scored 4 points
It seems as though the Round 2 game is the only score included in the SB calculation.
However, points should also be added for the Round 1 game. See 13.15.2 here: handbook.fide.com/files/handbook/C02Standards.pdf
"For tie-break purposes a player who has no opponent will be considered as having played against a virtual opponent who has the same number of points at the beginning of the round and who draws in all the following rounds. For the round itself the result by forfeit will be considered as a normal result. "
Therefore, in this case, the virtual opponent has 0 points before Round 1 (of course!), loses in Round 1 to the bye, and then in Rounds 3-6 is awarded the equivalent of a draw. So the Round 1 result is not just a full-point bye, but it for the purposes of SB calculation it the equivalent of a win against a player who scored 2.5 points. Therefore, this player's SB should have been 6.5.
13.15.3 is also relevant.