;;; The puzzle is: ;;; ;;; * * * * 2 * * 8 * ;;; * 6 8 5 * 7 1 3 * ;;; 4 * * * * 1 * 5 * ;;; ;;; * 7 * * * * * 2 * ;;; 9 * * * 6 * * 7 3 ;;; * 4 * * * 5 * * 9 ;;; ;;; * 2 * * * * * * 7 ;;; 3 9 6 * * * * * 1 ;;; * * * 4 * * * 6 * ;;; ;;; The solution is: ;;; ;;; 7 1 5 3 2 4 9 8 6 ;;; 2 6 8 5 9 7 1 3 4 ;;; 4 3 9 6 8 1 7 5 2 ;;; ;;; 6 7 1 9 4 3 5 2 8 ;;; 9 5 2 1 6 8 4 7 3 ;;; 8 4 3 2 7 5 6 1 9 ;;; ;;; 5 2 4 8 1 6 3 9 7 ;;; 3 9 6 7 5 2 8 4 1 ;;; 1 8 7 4 3 9 2 6 5 ;;; ;;; Rules used: ;;; ;;; Naked Single ;;; Hidden Single (defrule grid-values ?f <- (phase grid-values) => (retract ?f) (assert (phase expand-any)) (assert (size 3)) (assert (possible (row 1) (column 1) (value any) (group 1) (id 1))) (assert (possible (row 1) (column 2) (value any) (group 1) (id 2))) (assert (possible (row 1) (column 3) (value any) (group 1) (id 3))) (assert (possible (row 2) (column 1) (value any) (group 1) (id 4))) (assert (possible (row 2) (column 2) (value 6) (group 1) (id 5))) (assert (possible (row 2) (column 3) (value 8) (group 1) (id 6))) (assert (possible (row 3) (column 1) (value 4) (group 1) (id 7))) (assert (possible (row 3) (column 2) (value any) (group 1) (id 8))) (assert (possible (row 3) (column 3) (value any) (group 1) (id 9))) (assert (possible (row 1) (column 4) (value any) (group 2) (id 10))) (assert (possible (row 1) (column 5) (value 2) (group 2) (id 11))) (assert (possible (row 1) (column 6) (value any) (group 2) (id 12))) (assert (possible (row 2) (column 4) (value 5) (group 2) (id 13))) (assert (possible (row 2) (column 5) (value any) (group 2) (id 14))) (assert (possible (row 2) (column 6) (value 7) (group 2) (id 15))) (assert (possible (row 3) (column 4) (value any) (group 2) (id 16))) (assert (possible (row 3) (column 5) (value any) (group 2) (id 17))) (assert (possible (row 3) (column 6) (value 1) (group 2) (id 18))) (assert (possible (row 1) (column 7) (value any) (group 3) (id 19))) (assert (possible (row 1) (column 8) (value 8) (group 3) (id 20))) (assert (possible (row 1) (column 9) (value any) (group 3) (id 21))) (assert (possible (row 2) (column 7) (value 1) (group 3) (id 22))) (assert (possible (row 2) (column 8) (value 3) (group 3) (id 23))) (assert (possible (row 2) (column 9) (value any) (group 3) (id 24))) (assert (possible (row 3) (column 7) (value any) (group 3) (id 25))) (assert (possible (row 3) (column 8) (value 5) (group 3) (id 26))) (assert (possible (row 3) (column 9) (value any) (group 3) (id 27))) (assert (possible (row 4) (column 1) (value any) (group 4) (id 28))) (assert (possible (row 4) (column 2) (value 7) (group 4) (id 29))) (assert (possible (row 4) (column 3) (value any) (group 4) (id 30))) (assert (possible (row 5) (column 1) (value 9) (group 4) (id 31))) (assert (possible (row 5) (column 2) (value any) (group 4) (id 32))) (assert (possible (row 5) (column 3) (value any) (group 4) (id 33))) (assert (possible (row 6) (column 1) (value any) (group 4) (id 34))) (assert (possible (row 6) (column 2) (value 4) (group 4) (id 35))) (assert (possible (row 6) (column 3) (value any) (group 4) (id 36))) (assert (possible (row 4) (column 4) (value any) (group 5) (id 37))) (assert (possible (row 4) (column 5) (value any) (group 5) (id 38))) (assert (possible (row 4) (column 6) (value any) (group 5) (id 39))) (assert (possible (row 5) (column 4) (value any) (group 5) (id 40))) (assert (possible (row 5) (column 5) (value 6) (group 5) (id 41))) (assert (possible (row 5) (column 6) (value any) (group 5) (id 42))) (assert (possible (row 6) (column 4) (value any) (group 5) (id 43))) (assert (possible (row 6) (column 5) (value any) (group 5) (id 44))) (assert (possible (row 6) (column 6) (value 5) (group 5) (id 45))) (assert (possible (row 4) (column 7) (value any) (group 6) (id 46))) (assert (possible (row 4) (column 8) (value 2) (group 6) (id 47))) (assert (possible (row 4) (column 9) (value any) (group 6) (id 48))) (assert (possible (row 5) (column 7) (value any) (group 6) (id 49))) (assert (possible (row 5) (column 8) (value 7) (group 6) (id 50))) (assert (possible (row 5) (column 9) (value 3) (group 6) (id 51))) (assert (possible (row 6) (column 7) (value any) (group 6) (id 52))) (assert (possible (row 6) (column 8) (value any) (group 6) (id 53))) (assert (possible (row 6) (column 9) (value 9) (group 6) (id 54))) (assert (possible (row 7) (column 1) (value any) (group 7) (id 55))) (assert (possible (row 7) (column 2) (value 2) (group 7) (id 56))) (assert (possible (row 7) (column 3) (value any) (group 7) (id 57))) (assert (possible (row 8) (column 1) (value 3) (group 7) (id 58))) (assert (possible (row 8) (column 2) (value 9) (group 7) (id 59))) (assert (possible (row 8) (column 3) (value 6) (group 7) (id 60))) (assert (possible (row 9) (column 1) (value any) (group 7) (id 61))) (assert (possible (row 9) (column 2) (value any) (group 7) (id 62))) (assert (possible (row 9) (column 3) (value any) (group 7) (id 63))) (assert (possible (row 7) (column 4) (value any) (group 8) (id 64))) (assert (possible (row 7) (column 5) (value any) (group 8) (id 65))) (assert (possible (row 7) (column 6) (value any) (group 8) (id 66))) (assert (possible (row 8) (column 4) (value any) (group 8) (id 67))) (assert (possible (row 8) (column 5) (value any) (group 8) (id 68))) (assert (possible (row 8) (column 6) (value any) (group 8) (id 69))) (assert (possible (row 9) (column 4) (value 4) (group 8) (id 70))) (assert (possible (row 9) (column 5) (value any) (group 8) (id 71))) (assert (possible (row 9) (column 6) (value any) (group 8) (id 72))) (assert (possible (row 7) (column 7) (value any) (group 9) (id 73))) (assert (possible (row 7) (column 8) (value any) (group 9) (id 74))) (assert (possible (row 7) (column 9) (value 7) (group 9) (id 75))) (assert (possible (row 8) (column 7) (value any) (group 9) (id 76))) (assert (possible (row 8) (column 8) (value any) (group 9) (id 77))) (assert (possible (row 8) (column 9) (value 1) (group 9) (id 78))) (assert (possible (row 9) (column 7) (value any) (group 9) (id 79))) (assert (possible (row 9) (column 8) (value 6) (group 9) (id 80))) (assert (possible (row 9) (column 9) (value any) (group 9) (id 81))))