Optimal Strategy for the 20 / 11 position in Jail Blackjack
| ----- | 20 | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 11 | ----- | 13.48% | 6.74% | 10.11% | 8.42% | 9.26% | 8.84% | 9.05% | 8.95% | 9.00% | 8.97% | 7.17% |
| 0 | 13.48% | 13.48% | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0.5 | 1 |
| 1 | 6.74% | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0.5 | 1 | 0 |
| 2 | 10.11% | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0.5 | 1 | 0 | 0 |
| 3 | 8.42% | 0 | 0 | 0 | 0 | 0 | 0 | 0.5 | 1 | 0 | 0 | 0 |
| 4 | 9.26% | 0 | 0 | 0 | 0 | 0 | 0.5 | 1 | 0 | 0 | 0 | 0 |
| 5 | 8.84% | 0 | 0 | 0 | 0 | 0.5 | 1 | 0 | 0 | 0 | 0 | 0 |
| 6 | 9.05% | 0 | 0 | 0 | 0.5 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| 7 | 8.95% | 0 | 0 | 0.5 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 8 | 9.00% | 0 | 0.5 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 9 | 8.97% | 0.5 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 10 | 7.17% | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Explanatory notes:
First row - possible moves by the 1st player (blue).
First column - possible moves by the 2nd player (blue).
Second row - probability of the 1st player making the corresponding move, under the optimal strategy (yellow).
Second column - probability of the 2nd player making the corresponding move, under the optimal strategy (yellow).
The matrix elements - the value of the corresponding outcome for the 2nd player. Naturally, the value of the outcome corresponding to "0" moves by both players is the value of the position itself.