Board classification Queens Level 4. Dimensions 6×6. Region sample count 6. Observed pattern: tight-region board. Placement vector: R1C5, R2C3, R3C6, R4C2, R5C4, R6C1.
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 1 to 12 cells — smaller regions often pin a queen to a single row intersection.
Sample placement 1: R1C5. Constraint class: regionPin. Region 3 only touches row 1 once on this board, so its queen must land at column 5.
Sample placement 2: R2C3. Constraint class: elimination. Row 2, column 3 is the forced queen once region 2, row, column, and touch rules are applied together.
Sample placement 3: R3C6. Constraint class: regionPin. Region 4 only touches row 3 once on this board, so its queen must land at column 6.
Sample placement 4: R4C2. Constraint class: elimination. Row 4, column 2 is the forced queen once region 1, row, column, and touch rules are applied together.
Sample placement 5: R5C4. Constraint class: rowScan. After eliminations, row 5 has one legal square left — column 4.
Sample placement 6: R6C1. Constraint class: regionPin. Region 6 only touches row 6 once on this board, so its queen must land at column 1.
Lab result: Tight-region board. Coordinates R1C5, R2C3, R3C6, R4C2, R5C4, R6C1.