I would like to see the rest of the crank but I suspect it’s a Shimano FFS crank and its backwards Octa-joint bottom bracket. In order to remove the cups, you need an early Shimano freewheel tool, TL-FW20. These are rare but can be found. It fits the splines in the cups and they unscrew like other English-threaded cups: right side cup is left-hand threaded.