Ah, the trench knife. Not particularly ancient technology, but I think it’s one of the better anti-zombie weapons out there. Shotguns may seem fun, but they’re messy and noisy. Chainsaws are noisy as hell, make a huge mess and are dangerous to use. Swords get stuck but may be effective when used properly. The trench knife gives you a lot of freedom of movement, has a great way to crack a skull as well as a long blade to use as a survival knife. May take some getting used to, but I’d rather use one of these than swing a bat around.
Of course, I’d rather not have a zombie apocalypse to begin with. Those are best confined to virtual media.