What is the Pokéwalker?

The Pokéwalker is a small pedometer shaped like a Poké Ball, bundled with every copy of Pokémon HeartGold and SoulSilver in 2009 and 2010. It is the descendant of the Pokémon Pikachu toys of the Game Boy Color years, rebuilt for the DS: you transfer one Pokémon from your game into it, clip it to your belt, and your real footsteps become the game's.

The connection is the clever part. The walker talks by infrared directly to the HeartGold or SoulSilver cartridge, which carries its own infrared transceiver for the purpose, or walker to walker between friends, at a range of about five centimetres. Your Pokémon gains experience as you walk. Every 20 steps earns one Watt, the walker's currency, spent inside the device on the Poké Radar, which flushes out wild Pokémon on your route at 10 Watts a use, and the Dowsing Machine, which finds items for 3.

There are 27 routes to stroll, each stocked with its own wild Pokémon and items, and only two are open at the start. Lifetime Watts unlock the rest one stroll at a time, up to Quiet Cave at 100,000 Watts. Bulbapedia's arithmetic is famous: at roughly 2,000 steps to a mile, unlocking every route takes a minimum of about 1,000 miles of walking, some 200 days at 10,000 steps a day.

Special routes arrived by other roads: Yellow Forest came as an event download, Night Sky's Edge opened to players who transferred a Jirachi, and Beyond the Sea rewarded a foreign trade on the GTS. Because the walker and the cartridge talk locally, the whole system still works today; only the downloadable routes are stranded in the past.