The New York Times Hard level sudoku game is at this link: www.nytimes.com/puzzles/sudok... I used the solver on the sudokuexchange.com website to play this game.
I got a speedy 12 and a bit minute solution today. Admittedly I didn't go entirely notation free. I thought it would be useful to identify a few2 or 5 cells in case I could use the remote pairs technique. Not needed it as things turned out.
