I am fairly certain that they are essentially random. The qualifiers on that are: 1. The field is stratified -- that is they put together a ranked list of all registered pairs, and rank them by ACBL points (or perhaps BBO points in non-ACBL tournaments). 2. A roughly equal number of A, B, and C pairs are put into each section and each direction. This sometimes fails; I looked at a recent tournament I played in and saw that some sections had 9 B and 4 C pairs, some were 10 and 4 or 5, and one section was 11 and 6). 3. The assignment of seats in a section seems to be random; at least, I know I've played against two top-tier pro pairs in a row. In a 15-table section with 10 B and 5 C pairs and an even distribution, you'd normally expect to play an A pair, a B pair, and a C pair before you played a second pair of any particular strat. 4. In physical tournaments, There are one or two tables in each section and direction reserved for top pros, other tables (usually odds) that will tend to have "A" players, and the rest of the tables are typically going to be B and C players (taking into consideration whatever flighting or stratification is going on). There doesn't seem to be that kind of rigidity in the BBO Speedball games. So -- who you play against in your section will be pretty much luck. Much of the above is based on observation fueled by experience, not insider knowledge. I'd welcome ACBL or BBO corrections to my surmises above. Oh -- what I am almost certain does NOT happen is: - You don't get matched with a pair with an equivalent record in that event (if you are having a 60% game, they don't look for a pair with a 60% score for you to play against next round - If you have a certain number of Masterpoints, BBO does not look for a pair with an equivalent rank for you to play next round. Once the tournament starts, the movement has been set.