Mazda H platform
Note that a number of Mazda vehicles have similar platform codes but are unrelated. The following vehicles use the Suzuki H platform, not the Mazda H platform:
Prior to 1981, Mazda coded this platform as "LA" in the VIN.
The HB platform was introduced in 1981 as the Mazda Cosmo coupe and Mazda Luce/929 sedan. The Luce was updated in 1986, with the 929 following the next year for some markets, but the Cosmo continued on the HB platform until 1989.
The Luce nameplate was retired in favor of Sentia, but the H platform continued with the 1991 HD revision.