Pokémon Red and Blue/Rock Tunnel
Rock Tunnel is the only way to get from Route 10 to Lavender Town. Unlike the caverns beneath Mt. Moon, Rock Tunnel is pitch black, and you must rely on the Flash technique (HM 05) to light your way. Use the labeled maps to follow the ladders through the tunnel to the exit. The tunnel has two levels, but there really is only one main path.
 Into the dark
The wild Pokémon in Rock Tunnel tend to attack more often than their above-ground cousins, and if you're being attacked every few steps, it may take you awhile to reach medical attention. For that reason, it's a good idea to bring either a Pokémon that knows Dig, or plenty of Escape Ropes just in case you need to make a quick getaway. If you don't have either of those, this would be a good time to try Repel, which keeps weak Pokémon at bay.
You'll have a very difficult time, however, avoiding the many trainers lurking in the shadows. You'll have to use Flash if you want to see where you're going in here. It's possible to proceed without it, but you'll probably want the light so you can avoid some of this area's tedious, difficult trainer encounters. If you want to avoid a battle, walk a path that's far away from the trainer or that's out of the trainer's line of sight.
|#66 Machop||#95 Onix|
|Machoke at level 26, and then into Machamp once they're traded. Hitmonlee is probably a better option, especially if you can't trade, but Machop is available earlier.|