Teaching Queens Level 3: start with region scans on this 6×6 board. 6 regions, sizes 2–11. Walk students through 6 placements ending at R1C4, R2C6, R3C2, R4C5, R5C3, 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 2 to 11 cells — smaller regions often pin a queen to a single row intersection.
Lesson step 1: show why R1C4 is forced. Row 1, column 4 is the forced queen once region 2, row, column, and touch rules are applied together. Ask: which rows/columns/regions are now closed?
Lesson step 2: show why R2C6 is forced. Row 2, column 6 is the forced queen once region 3, row, column, and touch rules are applied together. Ask: which rows/columns/regions are now closed?
Lesson step 3: show why R3C2 is forced. Row 3, column 2 is the forced queen once region 1, row, column, and touch rules are applied together. Ask: which rows/columns/regions are now closed?
Lesson step 4: show why R4C5 is forced. After eliminations, row 4 has one legal square left — column 5. Ask: which rows/columns/regions are now closed?
Lesson step 5: show why R5C3 is forced. After eliminations, row 5 has one legal square left — column 3. Ask: which rows/columns/regions are now closed?
Lesson step 6: show why R6C1 is forced. After eliminations, row 6 has one legal square left — column 1. Ask: which rows/columns/regions are now closed?
Recap: 6 queens, 6 regions, one solution path. Replay using region-first scanning.