Also called SCRAMBLED MITCHELL
As already pointed out in a Mitchell movement there are two fields (N-S and E-W) and as such the movement produces two winners. Where one winner is needed and a Howell movement is not suitable because of the size of the movement, the solution is to have a switched Mitchell. The switched Mitchell is the same as an ordinary Mitchell in that there are two fields (N-S and E-W) in the movement and they only play against each other. The difference arises in the comparison of the scores with the N-S pairs playing as E-W on some of the rounds. This is usually achieved by switching the board through 90 degrees rather than the players changing positions. The comparison of the scores can never be perfect in this movement. (See Howell Movements for further treatment of balanced movements).
There are a few methods of conducting switched Mitchells. In the first the director announces each round where boards are to be arrow-switched, as it occurs. This means the board is played with the N position of the board pointing E or W on that round so that the E-W pair is playing as N-S. This also means that the E-W pairs cannot have the same pair number as their original table number, as this would confuse their results with their first N-S opponents. This can be avoided by adding the highest-numbered table number to the pair number of each E-W pair. For example in a 7-table movement all the E-W pairs would add 7 to their original table number to determine their pair number.
The recommended rounds where the switches are to occur has been debated since the creation of the movement. Dr. Ross Moore's paper on the subject has produced the definitive answer to this debate. Summarising his findings, the following table shows his simplest recommendations. If you require the best implementations available see his paper. Note where only one switch is shown it may be on any round and is shown as the first round for convenience. Where the number of tables is odd and two rounds are switched, they may be any two consecutive rounds and are shown as the first two. In the even numbers of tables there is no switching at table 1 which is assumed to be in the pair of sharing tables.
TABLES SWITCH ON ROUND
4 1
5 1
6 1
7 1
8 1
9 1
10 1
11 1
12 1, 6
13 1, 2
14 1, 5
15 1, 2
16 1, 8
17 1, 2
18 1, 9
19 1, 2, 5
20 1, 2, 5
21 1, 2, 5
22 1, 2, 5
23 1, 2, 5
24 1, 2, 5
25 1, 2, 6, 9
26 1, 2, 6, 9
27 1, 2, 6, 9
28 1, 2, 5, 16
29 1, 2, 6, 9
30 1, 2, 6, 9
31 1, 2, 6, 9
32 1, 2, 5, 12
33 1, 2, 6, 9
A second method of conducting the switched Mitchell (for an odd number of tables) is called the Bofors Mitchell after the town in Sweden from where the switched Mitchell, and in particular this movement, originated. The field is divided into two groups (but not a N-S group and an E-W group). With N tables in the movement, where N is odd, the pairs in group one are numbered from 1 to N and in group two from N+1 to 2N. Call the first group "A" and the second "B". The above schedule for switching is then used to seat group "A". For example in a 13 table movement, pairs 1 and 2 sit at E-W 1 and 2 respectively, and pairs 3 through 12 sit N-S at their respective tables. Group "B" fill in the remaining positions. When the change is called, group "A" move up 1 table, occupying the position vacated by the pair in group "A" at that table. Group "B" follow pairs in group "B" while moving down 3 tables. The boards move down 1 table. The Bofors Mitchell is particularly useful (with guide cards for the pairs) in the combined Howell-Mitchell.
As the above schedules for table switching do not produce perfect comparisons, and in particular as there is invariably one table that "forgets" to switch, it is not necessary to have the best available switching. In fact this next method of switching is easily the most practical, and is recommended for all switch Mitchells at the club level where the number of tables is typically a low number. Adequate comparison of pairs is obtained by switching just one round, preferably the first or last.
Care must be taken when scoring a switched Mitchell and it is particularly important that the pair sitting N-S should enter the score on the score sheet next to their number.
