The collective name for Falcom's sound production staff, originally founded by Mieko Ishikawa in late-1988. This alias first appeared in Star Trader (as simply "J.D.K."), released in March 1989. The unit got later renamed to "Falcom Sound Team J.D.K." in early 1990, and the "J.D.K." pseudonym got renamed to "jdk" with the release of Revival Xanadu in April 1995.

Since its formation, all composition and arrangement duties in Falcom games has been conducted under the name of "Falcom Sound Team jdk (J.D.K.)". For this reason, although its members are credited in-game, the composer/arranger of each individual track remains officially unknown. In addition to this, all Falcom music composed pre-1989 has been retroactively attributed to the "Sound Team J.D.K./jdk" moniker. Such is the case with Yuzo Koshiro's work.

(Not to be confused with "jdk (J.D.K.) BAND", a freelance unit that performs arrangements of Falcom music at live concerts, arrange albums and so on. Since the performers are contractors/not Falcom employees, they are not part of Sound Team jdk and do not compose Falcom music. There's a few exceptions, like Toshiharu Okajima and Noriyuki Kamikura, who have composed music for Falcom between 2012 and 2014, but their authorship has been bought by Falcom and attributed to "Sound Team jdk", similarly like they did with Yuzo Koshiro's compositions back when he left Falcom after completing work on Ys II in mid-1988. The same has been done with Yukihiro Jindo and Mitsuo Singa's contracted work for Falcom.)