The arcade version of Tekken 5 was released in 2004.
Namco developed Tekken 5 as the fifth main entry in the fighting-game series and released it for arcades in 2004. It was built for the Namco System 256 arcade hardware and marked the series’ tenth anniversary. The game returned to more traditional, fluid stages after Tekken 4 experimented with uneven terrain and interactive environments.
The home version followed on PlayStation 2 in 2005. That release added modes and content, including Devil Within, and also included arcade versions of earlier Namco games. This difference in dates is the most common source of confusion: 2004 refers to the original arcade release, while 2005 refers to the PlayStation 2 version.
Tekken 5 later received arcade updates. Tekken 5.1 arrived on July 14, 2005, with balance changes, and Dark Resurrection followed later in 2005 before receiving portable and PlayStation 3 versions. These updates do not change the original arcade debut year, so 2004 is the correct answer.