The max is 24, and when they overstepped that with 48 strokes once, the recipient had to be hospitalized. I don’t know how it’s so harmful, but it is.

https://en.m.wikipedia.org/wiki/Caning_in_Singapore

Minor? Canning is hardcore, it basically aimed at the exact spot in full strength and it will split open your ass cheek horizontally that even a masochist will yell stop. It's a severe punishment for severe crime, one level lower than death sentence, where after each session you wouldn't be able to walk and sit for weeks.

20 strokes will likely split into somewhere between 5 or 6 sessions over the year of imprisonment

To my understanding, 24 is the max. Caning is pretty devastating to the body. If your intent is not to execute, you have to have some restraint.

20 strokes of a cane can be really traumatizing, and from the sound of it, it's an individual who has been specially trained to Inflict as much pain as possible. Also if they act out during their prison stay they'll likely get more.

I think the addition of a physical punishment is useful in cases of rape, as it shows them a glimpse of how painful the violation of one's autonomy is.

You've never been caned in Singapore, I gather?

I wouldn't quite say that, no: https://www.dw.com/en/the-invisible-scars-left-by-strikes-of-the-cane/a-18298970