For more information on rover pairs, see the section on "rovers" in the Mitchell movement. Here the procedure is the same, except that the rover moves in a different pattern.
Where the number of tables is prime, the roving pair starts at table 2 on the second round and moves up one table at each change (this assumes that the boards are moving down one table).
Where the number of tables is even, but not divisible by 3, then the rover starts at table 2 and moves up one table at each change, skipping one table at the same time the E-W pairs skip a table (i.e. after N/2 rounds).
Where the number of tables is divisible by3, the movement is irregular so that guide cards are necessary.
It should be noted that the rovers must repeat against some E-W pairs so that there is no repetition of the N-S pairs displaced. As the even numbered table movements have the revenge round in the last round, this feature of the rover is not as undesirable as it would first appear.
The real advantage of the rover movement is in having all the boards played an equal number of times. In all the schedules given below, the roving pair sits out for the first round, and after that replaces the N-S pair at the table shown in the schedule. The displaced N-S pair return to their own table at the end of that sit out round. The whist movement assumed to be in use is: E-W pairs down 2 and the boards down one.
6 Tables: 1, 2, 4, 5, 6 *
9 Tables: 1, 2, 3, 5, 7, 4, 9, 6 *
12 Tables: 1, 2, 3, 4, 5 *, 6, 8, 9, 10, 11, 12 *
15 Tables: 1, 2, 3, 4, 5, 7, 8, 10, 11, 6 *, 13, 14, 9 *, 15
18 Tables: 1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16 *, 18
* Indicates a repeat against an E-W pair.
In the last movement, for 18 rounds to be played the roving pair must displace an E-W pair at table 15 or 1, but note the N-S pairs at these tables have been displaced on previous rounds. Used in conjunction with a switched movement this is not noticeable.
