The beach that the map in your spot guide refers to is this one. It's not called 'Paishawan', it's called 'Shalun' (??). Also, you're not allowed to step foot beyond that rope line because the beach is off-limits. If you're caught, you can be subjected to a fine between NT$5000-NT$20000! Apparently because there have been a number of drownings here. And the local government is stupid.