Are Pokémon Diamond and Pearl covers the same in Japan and the West?
For the first DS generation, the answer is a clean yes. Dialga fronts Diamond and Palkia fronts Pearl in Japan and in the West, in the same key artwork: the legendary Pokémon rendered large over a deep, jewel-toned ground, blue for Diamond and a rose pearl tone for Pearl. Platinum followed the same rule two years later, with Giratina in its new Origin Forme on the box in every region.
What changes is the furniture. Japanese boxes carry the Pocket Monsters wordmark and a CERO rating mark; Western boxes carry the international Pokémon logo and an ESRB or PEGI rating, with the version name set in English. The spine and rear panels are laid out to each market's habits, but the painting at the centre of the box does not change, and neither do the cartridges' identities: the mascot you see is the mascot you meet at Spear Pillar.
That consistency was itself a step. The Game Boy and Game Boy Advance generations had occasionally redrawn or rearranged cover art for the West; by 2006 the series had settled into a single global image per version, and Diamond and Pearl's boxes read as one product worldwide, translated rather than reimagined.
For a shelf, the pairing is the point: a Japanese and a Western Diamond box side by side show the same Dialga twice, framed by two different ideas of what a game box should say. The pictured pair on this page is the comparison to study.