Well MC said that once mastered swordmanship in that world it is no different from magic with them being able to cleave mountains and etc. So just like MC said, the father probably did go easy on him a lot and fight on some restriction most likely. Otherwise for being one of the few Sword Master in that kingdom, his skill would've been very lackluster.
I don’t quite get how he’s been able to beat Harold so often, like is he a sword master now? Or iwas Harold fighting with a restriction?
Well MC said that once mastered swordmanship in that world it is no different from magic with them being able to cleave mountains and etc. So just like MC said, the father probably did go easy on him a lot and fight on some restriction most likely. Otherwise for being one of the few Sword Master in that kingdom, his skill would've been very lackluster.