Underground Path (Kanto Routes 5-6)

The Underground Path (Japanese: ちかつうろ Underground Path) between Routes and  is located directly underneath Saffron City and terminates just to the north and to the south of Saffron City.

In Generations and, the path is the only way to travel between Cerulean City and Vermilion City until the gates surrounding Saffron City are opened, which does not occur until their guards receive a drink from Celadon City. In Generations and, both entrances to the path are blocked until the problem at the  is solved.

Route description
The path is a long, dark hallway that travels under Saffron City. Despite the cave-like lighting of the path, there is no threat to be attacked by wild Pokémon. Occasionally, by using an Itemfinder or Dowsing MCHN, items that s have dropped along the path can be found and retrieved.

In Generations I and III, a girl in the Route 5 gate is willing to trade Pokémon with the player. In, and , she asks for a in exchange for a ; in , and , she requests a  in exchange for a ; in , she offers a  (which will immediately evolve into  after being traded) in exchange for a ; and in , she wants to trade her  for a.

Differences between generations
Across all generations, the design is virtually the same, only with updated graphics, although it is much shorter in Generations and. In Generation IV, a man is in the Underground Path who will trade for the RageCandyBar that can be bought in Mahogany Town.

In Generation II only, the Underground Path is a map location in the Pokégear.

In the Pokémon Adventures manga
Although the Underground Path doesn't make an actual appearance in Pokémon Adventures, the map of 's journey in shows that he used it as a shortcut to Vermilion City between ...But Fearow Itself! and Danger: High Voltorb.