What arcade hardware did Tekken 4 originally use?

Tekken 4 originally used Namco System 246 arcade hardware.

Namco System 246 was an arcade platform based on PlayStation 2 technology, making it a natural successor to the PlayStation-based boards used by earlier Tekken games. Tekken 4 was first released in arcades in 2001 and later ported to the PlayStation 2 in 2002.

The hardware change supported Tekken 4’s darker visual style, more detailed arenas, and experimental environments. Unlike earlier entries that largely kept fighters inside open arenas, Tekken 4 introduced walls and confined spaces that affected movement, combos, and strategy. Its arcade version also featured fewer characters than the expanded console release.

The main confusion is between Namco System 246 and the System 11 or System 12 boards used by earlier games. Tekken used System 11, while Tekken 3 and Tekken Tag Tournament used System 12. Namco System 357 belongs to a later generation of arcade hardware and is associated with newer PlayStation 3-era titles, not Tekken 4.