THE LIBRARY

Ruby and Sapphire at 16.22 million, the remakes at 12 million, Emerald at 6.32 million: the GBA generation's sales ladder, rung by rung.

The first Pokémon games for the Nintendo DS: a new region, Sinnoh, 107 new Pokémon, online trading, and the physical and special split.

Surfing crawls at walking speed, battles amble, and snow and mud drag at your feet. Platinum quietly sped the worst of it back up.

Before 2006, a move's type decided whether it hit physically or specially. Generation IV judged every move on its own, and battles changed for good.

The GTS let you leave a Pokémon on a worldwide shelf, name your price in another Pokémon, and come back later to find the trade done.

Beneath all of Sinnoh runs a second map: dig for fossils and spheres, build a Secret Base, set traps, and steal your friends' flags.

Place an Odd Keystone in a ruined tower, then go underground and greet other players 32 times. Spiritomb is Generation IV's most social Pokémon.

Sinnoh's wrist computer fills the DS touch screen with 25 little applications, from a pedometer to a radar for roaming legendaries.

Platinum is the expanded Sinnoh: a bigger Pokédex, a trip inside Giratina's world, a Battle Frontier, and the speed fixes players asked for.

Giratina's exile dimension, reached at the top of Mount Coronet: a place where time does not flow, platforms float sideways, and you surf down waterfalls.

Each Sinnoh game hides a handful of species from the other: Dialga against Palkia, one fossil against the other, and Platinum loosening most of it.

Sinnoh's own dex holds 151 of the world's 493. The rest took the other version, Game Boy Advance cartridges, a spin-off game, and events.

The DS had two cartridge slots, and Generation IV used both: a Game Boy Advance game underneath changed the wild Pokémon and fed Pal Park.

The one-way border crossing between generations: migrate six Pokémon from a Game Boy Advance game, then catch them again in a timed show.

Mostly by download: key items over Wi-Fi that unlocked Darkrai and Shaymin, Pokémon handed over directly, and one famous egg from another game.

The Arceus event was finished, hidden in every Sinnoh cartridge, and then shelved. Junichi Masuda later said it was judged too confusing for players.

Japanese copies shipped with a door you could surf through into the black space between maps, and players walked it to Darkrai and Shaymin.

Yes, in every way that matters: Dialga and Palkia front both regions' boxes with the same artwork. What changes is the branding around them.

Seven months apart, and not quite the same game: Japan's launch copies carry a famous glitch the West never saw, fixed before the games crossed the Pacific.

Five facilities, five bosses, one shared design in two regions: Platinum and the Johto remakes built the same Frontier in Sinnoh and Johto.

The Gold and Silver remakes: Johto and Kanto rebuilt for the DS, a Pokémon walking behind you, and a pedometer in every box. 12.72 million sold.

A Poké Ball-shaped pedometer bundled with HeartGold and SoulSilver. Walk in real life, and your Pokémon levels up, finds items and unlocks 27 routes.

It began as Yellow's tribute to the anime: one Pikachu, on foot. The remakes gave the trick to all 493 species and made it the pair's signature.

Johto's answer to Contests: three Pokémon per team, ten track-and-field events, five courses, and juice blended from Apricorns to train for them.

Yes: Ho-Oh and Lugia front both regions' boxes in the same art. The real difference is the box itself, a big one, built to hold the Pokéwalker.