Because of the 123 in the bottom-left box in row 7 which draws your attention to that row, I certainly got the 8 at 0:19 by looking for digits in the bottom that were not 123 but could be forced into row 7. There's only one spot for the 8 in that row at the start, and you can trivially put a 4 to the left of the 8 as well although I manage to move around the whole puzzle for a long time before coming back to do that.
u cant put 8 below 9 and next to 1, cos there's already an 8 in the row... and the bottom right corner box already has 8 which means that 8 MUST go where he put it in 00:19
How he figured out the 1 is pretty impressive before the 8 at mark 19 sec. He gets the 8 by using elimiation because it cant be the bottom three in cell H because of the 8 on the bottom of cell i. cant be the left boxes of cell H cuz of the 8 in left cell of 8. which leaves the top middle and middle squares as possibilities. Look at cell G, only 8 can be in middle, which means that in cell H it cant be middle square, which means it middle top.
he's quite fast. it will take me at least 8 minutes when solving hard one. solving sudoku puzzle is like solving engineering mechanics problem, where you can make assumptions.
You could have made this video more exciting by explaining what you do. I recognize the solving methods from a book... writing the candidate numbers on the lines. I think it's faster to just keep them in your head.
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