Case LinkedIn Queens #807: 9×9 grid, 9 colored regions. Nine exhibits — queen coordinates R1C5, R2C8, R3C3, R4C1, R5C7, R6C2, R7C9, R8C4, R9C6. No two queens may share row, column, region, or adjacency.
Board spotlight: Several color regions span only a few cells — scan those regions first because they often force a queen into a single row or column. Region sizes range from 4 to 33 cells — smaller regions often pin a queen to a single row intersection.
Exhibit 1: queen at R1C5. Row 1, column 5 is the forced queen once region 3, row, column, and touch rules are applied together.
Exhibit 2: queen at R2C8. Row 2, column 8 is the forced queen once region 4, row, column, and touch rules are applied together.
Exhibit 3: queen at R3C3. Region 2 only touches row 3 once on this board, so its queen must land at column 3.
Exhibit 4: queen at R4C1. Row 4, column 1 is the forced queen once region 1, row, column, and touch rules are applied together.
Exhibit 5: queen at R5C7. Row 5, column 7 is the forced queen once region 5, row, column, and touch rules are applied together.
Exhibit 6: queen at R6C2. After eliminations, row 6 has one legal square left — column 2.
Exhibit 7: queen at R7C9. Region 8 only touches row 7 once on this board, so its queen must land at column 9.
Exhibit 8: queen at R8C4. After eliminations, row 8 has one legal square left — column 4.
Exhibit 9: queen at R9C6. After eliminations, row 9 has one legal square left — column 6.
Verdict: placement set R1C5, R2C8, R3C3, R4C1, R5C7, R6C2, R7C9, R8C4, R9C6 is consistent with every rule. Case closed.