A lot of people insist that this is the way. However, at some point, I figured out that making the horizontal cut (or cuts) before you make vertical cuts is a lot easier. You can do it by simply putting the onion with the root on the board and cutting down at an angle of about 5-10 degrees. When the tip of the knife hits the board, simply don't press down all the way to keep the root intact. Then put it down normally and make the vertical cuts. You can easily manage 3 or 4 horizontal cuts this way. And there's no awkward cutting towards yourself with a sharp knife. All this business of first making lots of vertical cuts and then attempting a horizontal cut is a lot more fiddly. The vertical cuts affect the structural integrity of the onion. This makes the horizontal cuts harder. And it also makes the process of dicing harder.
Of course, as the article points out, the horizontal cuts don't really do much that a chef should care about. You can dice an onion super fine with just vertical cuts very close together. And it's a lot faster and easier. You might angle some of the cuts towards the edges. But honestly, even that is unnecessary and a bit overkill. With a good knife, you can put the vertical cuts really close together. So close that any kind of angle would mean the cuts cross each other. Once you are that close, a horizontal cut really does not matter. And if you do a rough cut, the size matters even less.
If you are interested in this topic, there's a French chef on Youtube called Jean Pierre who is full of practical wisdom and techniques. You can learn a lot from him. And he's highly entertaining to watch too. He's very opinionated on onions. Or Onyo as he pronounces it. You won't see him making horizontal cuts, ever.
Of course, as the article points out, the horizontal cuts don't really do much that a chef should care about. You can dice an onion super fine with just vertical cuts very close together. And it's a lot faster and easier. You might angle some of the cuts towards the edges. But honestly, even that is unnecessary and a bit overkill. With a good knife, you can put the vertical cuts really close together. So close that any kind of angle would mean the cuts cross each other. Once you are that close, a horizontal cut really does not matter. And if you do a rough cut, the size matters even less.
If you are interested in this topic, there's a French chef on Youtube called Jean Pierre who is full of practical wisdom and techniques. You can learn a lot from him. And he's highly entertaining to watch too. He's very opinionated on onions. Or Onyo as he pronounces it. You won't see him making horizontal cuts, ever.