Unique Rectangle Type 1

The following four Unique Rectangle techniques are quite similar, with only a few small differences. Let’s take a look at the first one – Unique Rectangle Type 1

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1. Take a look at this example. We have three pure bi-value cells and one cell containing an additional candidate. So we are looking at Unique Rectangle Type 1

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2. If 3 or 9 were placed in this cell, it would create what some refer to as a “deadly pattern” because the puzzle would no longer be unique – we would get more than one valid solution for this grid configuration. So we can safely remove this pair from the cell