Unique Rectangle Type 3

Unique Rectangle Type 3 has two floor cells with only the deadly pair and two roof cells with extra candidates. The extras in the roof cells form a pseudo-locked set with other cells in their shared house, allowing eliminations.

Technique

1. Find a potential deadly rectangle with candidates {X,Y} across two boxes.
2. Two cells (floor) have only {X,Y}; two cells (roof) have extras beyond {X,Y}.
3. The roof cells' extra candidates, combined with other cells in their shared house, form a locked set.
4. Eliminate the locked set's candidates from other cells in that house.

Tips

• Type 3 is more complex than Types 1 and 2 because it involves a pseudo-locked set.
• The roof cells' extras effectively act as a Naked Pair/Triple with neighboring cells.
• Check the shared row, column, or block of the roof cells.