Pokemon Pearl and Diamond for the Nintendo DS came out in Japan on September 28. Media Create is responsible for tabulating sales data in Japan, and they've updated their website reflecting the new releases.
In the four days after the pair of DS Pokémon games were released, the two combined to sell over 1.58 million units. To be exact, that's 820,047 copies of Pokémon Diamond, and 768,687 copies of Pokémon Pearl. Lumping the two back together, our math reveals that averages out to about five copies sold per second, or $725,000 worth of sales per hour. (There are a lot of hours in four days.)
We know the Japanese are crazy about the DS, and we know they've always been crazy about Pokémon. A game release which is the combination of the two shows what power Nintendo has in the Japanese marketplace. Until Nintendo announces release dates for the rest of the world, Pokémaniacs will just have wait patiently until the time is right for them to hand over their money to Nintendo and catch them all for the umpteenth time.