Sudoku 129 Better Link Info

Once you identify a few "indexed" numbers, it can lead to a rapid chain reaction of placements that wouldn't be possible in a standard puzzle Sudoku 247 Hybrid Solving:

Eventually, this chain will lead to a contradiction (two 5s in the same box, or a cell with zero candidates). When you hit a contradiction, you know your starting assumption was wrong—the chain is impossible, and you can eliminate that candidate. This is pure logic at its finest. sudoku 129 better