I'm showing you tips and techniques in solving Soduku puzzles. I'll be showing you another example here of a master strategy called swordfish. We removed all the other notations just to make it easy to figure out. Those are the ones that can only be 4 in this example here. But just like our last strategy of X wings, this works over 3 instead of 2 columns. Basically, it says that if this one is a 4, this can't be a 4. So if this one's a 4, this can't be a 4 also. It's another way of eliminating options so doing the same way. It's basically just a 3 column X wing is what it basically is. It's just another way of eliminating values because you know if that is a 4, that can't be a 4, if this is a 4, that can't be a 4. It's good for later on because you keep that in mind when you take a look at this example when you fill in the rest of these values that you know if this one automatically becomes a 4, that one no longer can be a 4. That's basically another process of elimination. It's just like an X wing. However, over all 3 different columns and rows. In our next master technique, we'll show the technique of forcing chains.