I usually carry a 17"-bladed watermelon knife, but its ALWAYS kept in a scabbard strapped to my motorbike. No problems so far.
Seriously, though, I once asked the salesman in a cutlers about legal knives (he had some of those fancy 8" damascus steel stilettos and huge foot-long bowie knives) and he said they’re all legal. Then again, he was also selling powerful crossbows, blowpipes, etc., and I’m pretty sure they’re not legal, so go figure.
I expect it depends where you are – I’ve gone through police checkpoints while going hiking, carrying a machete that looks like a sword, with no problems. I’d imagine the cops wouldn’t like it much if they found me carrying it around in Dinghao, though.
My buddy and I were pulled over in Tainan in '97 for running a red light (it wasn’t really red; it was a T-intersection…! ) Anyways, both of us had Chinese broadswords strapped to our back as we had just finished a Kung-fu class.
The conversation went like this:
Policeman: You can’t carry these around.
Me: We are going home from our Kung-fu school, where we practice the sword.
Policeman: Then you have to leave it at the school.
Me: But we practice often at home.
Policeman: Then you have to leave it at home.
Me: But we have to study it at school…
His partner found it amusing, as he could tell we weren’t evil people hacking up innocent children and told him to just forget it. So we were let go. Didn’t even get a ticket for the red light…
I was thinking that his question was not about whether it’s allowed to have whatever size of knife in Taiwan, but whether he would have problems with the customs upon arrival.
Speaking of knives, does anyone know the English term for a 西瓜刀? Is it really ‘watermelon knife’? When I search for this on the Internet I get pictures of knives with a fancy coloured blade.