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| XGID=---A-BHA--C----------baab-:1:1:1:52:0:0:3:0:10 | |||||
Blue to play 52 | |||||
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| XGID=---A-BGB--C----------baab-:1:1:1:52:0:0:3:0:10 | |||||
Blue to play 52 | |||||
As Daniel and Michael are driving at, it helps to pay attention to even/odd. You need one crossover to bear a checker off, so having an ODD number of crossovers to bear in (from your own outer board) makes it even, and is usually better to lose an irrelevant crossover than waste pip(s).
The first position is the one you posted: O (Outer, 10/8 10/5) is correct, keeping an odd number of checkers in the outer board.
The second position is a variant with an extra checker on the 7pt (borrowed from the 6pt). In that case, it is better to waste the extra pip with J (Jump, 10/5 7/5).
In fact, O is a much bigger error than the second position than J is in the first position. Getting the outer board from even (four) down to odd (three) is the imnportant gain (though I believe you already understood that part).
A more advanced nuance to keep in mind is the value of having a checker on the 8pt when the 4pt is vacant (applicable here), and having a checker on the 10pt when the 5pt is vacant.
Nack