3-1 is the prison stage of the Tower of Latria yes, be careful, that's one of the most confusing stages in the whole game, right next to 5-2, plus it's filled with magic wielding guards that can kill you in one magic shot if you're not careful.
The other stages in which you can get Bows now is 4-1 and 4-2. There's a vendor in 4-1 and 4-2 who sells Short and Long Bows, and the Compound Long Bow can be found in the platform to the left of Vanguard which has a Silver Bow Skeleton at the top.
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CPU - i7 8700K 3.7 GHz (4.7 GHz turbo) 6 cores OC'd to 5.2 GHz with Watercooling (Hydro Series H110i) | MB - Gigabyte Z370 HD3P ATX | Gigabyte GTX 1080ti Gaming OC BLACK 11G (1657 MHz Boost Core / 11010 MHz Memory) | RAM - Corsair DIMM 32GB DDR4, 2400 MHz | PSU - Corsair CX650M (80+ Bronze) 650W | Audio - Asus Essence STX II 7.1 | Monitor - Samsung U28E590D 4K UHD, Freesync, 1 ms, 60 Hz, 28"
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