Dark Cave (Japanese: くらやみのほらあなDark Cave) is a single-level cave located in eastern Johto. Though it is not necessary to enter the cave to complete the storyline, Dark Cave is the only place in the Generation II games to capture wildDunsparce and Wobbuffet. As its name implies, Flash is required to illuminate the cave.
The cave is unique in that the cave is separated into two parts, yet the cave does not change floors between the two areas.
The northernmost point in the cave is at the entrance leading to and from Route 45 just south of Blackthorn City. The path of the cave makes a 90-degree turn to the right before proceeding south for a short distance to the first of two underground ponds in the cave. Trainers can Surf directly south to reach a Revive, to the southwest then to the north to reach a man who hands out the BlackGlasses, or to the southwest to make landfall near TM13 (Snore). West of TM13, the path from the BlackGlasses man merges with the TM13 path as it turns south and enters the southern portion of Dark Cave. Ledges on this side prevent access to Blackthorn City from the south via Dark Cave.
Immediately after emerging from the north half, the path comes to the second of two ponds. Trainers can Surf to the west from this point to snag a Potion and reach Route 31, or, if a Pokémon knows Rock Smash, they can also Surf to the south and dispose of a series of rocks as they head north and find a hidden Elixir and then eastward toward a Hyper Potion. Near the item, the path of the cave turns south, passing a Full Heal and a Dire Hit (in Crystal only) before reaching its southernmost point at Route 46.
In Generation IV, some of the rocks that can be broken with Rock Smash have been replaced with boulders that require Strength to be moved.