I'm showing you some tips and techniques in solving Soduku puzzles. The next strategy is called hidden pairs. In this example, we put all our notations where all the numbers can go, which you'll notice in this row right here, there is only two spots that 1 and 3 can be. Like the naked pairs, which can only be like there's no other ones hidden. This one here has a hidden 2 in there. You know that this can't be 1 or 3, that can't be 1 or 3, or that can't be 1 or 3, but 1 or 3 has to be in these two here. So you can eliminate 2 from that row right there. It may not lead to you immediately putting in another number, but it'll eliminate a possibility, which is basically get you one step closer to solving the puzzle. In our next clip, we'll be showing some master strategies called X wing.