All modern keyboards share the same feature- a small raised ridge on both the 'f' and 'j' key.
These ridges are put there for a very good reason. It's to help you type easier, and after finding out how, you'll realize that you've been using a keyboard wrong this entire time.
This feature was designed and implemented in 2002. It's to help you put your fingers in the correct places on the keyboard without actually looking at the keyboard.By using this feature, you can increase your typing speed exponentially.
To properly type, place your index fingers on 'f' and 'j.' This is the correct hand placement for typing.
As you can see, this is the correct hand placement technique. The left hand should cover a, s, d, and f. The right hand should cover, j, k, l, and ;. The thumbs cover the space bar.