XGID=-b----E-CA--dD---b-dba--AA:0:0:1:21:0:0:3:0:10
Unlimited Games. How should Red play 21?
Bar/24, 13/11 is too passive. Bar/22 is a reasonable try but a little loose.
There are two main choices: (a) Bar/23, 24/23 and (b) bar/23, 6/5.
(a) takes the security of an anchor so Red can then develop his forward position without fear of interruption.
(b) is riskier but takes advantage of the triplication of fours.
XG rates (a) as the best move but (b) is not an error. The question is: did you even consider (b)?
24/21.