See what happens with ham for example: you are cutting small dice for a recipe and want to push the ones already made to the side to make more room.

Automatically you push the ham dice using your knife blade.

Unfortunately, when you do this the knife edge will scrape the chopping board and blunt the blade.

The right gesture is to cut as normal, but when you need to push, turn knife upside down so that the sharp edge is on top.

Give a half turn to knife, like locking a door with a key, push chopped items, then turn knife back to usual position.

There is then no risk of damaging your blade.

Another example with an onion to chop: doing it badly, the edge scrapes on chopping board.

Doing it properly, it's the back of the knife which scrapes chopping board.