Toyota Dyna registered on 6 March 1988 would fall under the 5th generation of the Toyota Dyna/Toyoace line, which ran from 1985 to 1995.

Why this fits

The generation timeline places the 1988 registration date inside the 1985–1995 production span for the 5th generation. Toyota’s own vehicle lineage page also shows the Dyna 100/150 series entering the lineup in May 1985, which matches that generation window.

Note on registration date

A registration date tells you the vehicle’s first registration, not necessarily its exact manufacturing month, so the chassis/model code can refine the answer further if needed. For a March 1988 registration, the safest classification is 5th generation.

TL;DR: 6 March 1988 Toyota Dyna = 5th generation.