What is the void glitch in Pokémon Diamond and Pearl?

Diamond and Pearl's maps sit in a shared black space, and two glitches let players walk in it. The first only ever existed in Japanese copies. Due to a programming mistake, the door of Aaron's room in the Pokémon League could be Surfed through, stepping the player out of the room and into the void around it. From there, counting steps with the Pokétch pedometer app, a player could walk the nothing all the way to Newmoon Island and the Flower Paradise and catch Darkrai and Shaymin without their event items.

Nintendo acknowledged the Surf glitch officially, one of only two Generation IV glitches it ever owned up to, and removed it from later Japanese printings and from every international copy. The fix shaped event history: because the door had leaked, Darkrai and Shaymin were given out as direct Mystery Gift Pokémon for Diamond and Pearl rather than through their items, which were held back until Platinum, where the glitch is gone.

The second door never fully closed. Tweaking, also called holepunching after its discoverer, works across Generation IV: ride the bicycle fast across the seams where map sections load and the graphics can fail to arrive, opening a tear into the same void. Patient players charted routes through it to Darkrai, Shaymin and even the Hall of Fame in the Western games too.

One door in the void stays shut. Arceus cannot be reached this way: no Hall of Origin has ever been found in the void, and the encounter needs an event flag walking cannot fake. The void is also genuinely dangerous to a save file. Saving in the wrong patch of nothing can trap a player with no way out, or freeze the game on loading, which is why the step counters and escape plans in the old guides read like mountaineering notes.