The R31 "Iron Mask" Skyline, produced by Nissan from 1985 to 1989, earned its nickname from its distinctive, angular front end with slim, rectangular headlights and a bold grille. It marked a transitional phase between the classic boxy Skylines of the past and the more performance-oriented R32 that followed. Notably, some models featured the innovative RB-series engines, including the RB20DET, which laid the groundwork for Nissan’s legendary inline-six performance lineage.