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Sometimes, when you love an artist's work, you just find any opportunity you can to pay tribute to it. At least that's the only explanation I can come up with for this strange Easter Egg, which finds the 2002 song "Letters", performed by megaselling artist Utada, buried within the code of the 2005 GameCube release Mario Superstar Baseball.
The hidden song was discovered by Mario Superstar Baseball megafan Sean Coakley, finding the track hidden deep in the North American version during an asset-decompiling session.
The dsp-acdm file is nakedly listed as "Letters - Hikaru Utada", but has no direct prominence in the game itself, suggesting it was simply added in tribute to the Japanese-American artist. Coakley does not know whether the hidden song appears in the JPN edition of MSB, but no doubt intends to find out, as they continue a wealth of projects surrounding their favourite slugger.
For those less inclined, Hikaru Utada (or just "Utada") is a Japanese-American singer-songwriter who has seen huge success in both U.S. and Japanese music markets. Following the release of their 1998 debut album, "Precious", Utada has written and released numerous records, alternating between Japanese and English lyrics. They are known for their genre-blending style, which fuses J-Pop with Hip-Hop and R&B influences.
With over 40 million sales to date, Utada is recognised as one of the most successful Japanese singers of all time, noted as "The most influential singer of the ['00s]" by The Japan Times. This is not Utada's first appearance in gaming, and some of their singles - including "Face My Fears", "Don't Think Twice", and "Sanctuary" - have been featured in the immensely popular Kingdom Hearts series. "Letters", pulled from Utada's 2002 album "Deep River", debuted at No.1 in the Japanese charts on release.
Of course, none of which explains why it would be found amidst the line code of a Super Mario-themed baseball game. It doesn't seem like the sort of song considered for the game's soundtrack, so we can only assume that it was added purely as a good luck charm - a loving tribute of sorts - from a fan on the development team. But you certainly wouldn't catch me doing anything MEIKO KAJI like that.