The Hidden Unique Rectangle strategy is very similar to the unique rectangle strategy. The only difference is that there are more non-deadly numbers in some of the rectangle cells.

### One corner is a bi-value, and the other corners have a strong link between one of the deadly pattern numbers

In this type of hidden unique rectangles, one of the corners of the deadly pattern is a bi-value, containing only the deadly pattern numbers and no other numbers. The other cells have the deadly pattern numbers as well as other candidates. In addition, all of the squares except for the bi-value square have a strong link between one of the deadly numbers.

Because of the strong links, you can remove the other deadly number from the corner that is diagonally across from the bivalue square.

### A floor square has a strong link to one deadly pattern number in the roof square across from it

When one of the floor squares has a strong link to a deadly pattern number in the roof square across from it, you can remove the other deadly number from the other roof square.