system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does a knife thrower know that the blade will hit the target and not the handle?
gpt
The first thought is that it is a lot harder than the movies make it...

There are two ways of throwing a knife:
You can throw it so it travels blade first without rotating, which is harder to do with the same accuracy/power, but means it should always hit properly.
The alternative is to throw the knife so it rotates while in the air, and your aim is to have it blade first when it reaches the target - to do this you essentially need to be able to throw very consistently so it always rotates at the same speed, and then judge the distance very accurately - practise enough and you will learn a set of distances where the knife will be blade first, and then by stepping forwards or backwards you can align your target with one of these points so when the knife meets the target, it is correctly rotated.