Sudoku Tutorial
Remote Pair
remotePair.jpg This is similar to a COLORS technique except that it involves identical bivalue cells.

When a puzzle contains multiple matching  naked pairs, they can be colored in a alternating fashion as shown here.    As a result, either all of the red candidates are true or all the green candidates are true.  

Any cell that is visible to two alternately colored cells becomes a target.  A candidate that can 'see' a matching red and green candidate can be removed.

(These bivalue cells also form two X-chains and two XY-chains (you can ignore cell r9c5).  But the remote pair is much easier to spot and it eliminates two candidates at once) 

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