In what year was Pokémon Diamond & Pearl released in Japan?

Pokémon Diamond and Pearl were released in Japan in the year 2006. These games marked the start of the fourth generation of the Pokémon video game series, introducing a new region called Sinnoh, along with new Pokémon species, gameplay features, and enhanced graphics compared to the previous generation. The release of Diamond and Pearl in Japan was highly anticipated by fans, and they quickly became best-selling titles, further cementing Pokémon's popularity and success in the gaming industry.