Norinco Type 99 Main Battle Tank
The majority of the information given below was gleaned from online sources, since this particular tank is a modern, active and for the most part classified the information is very limited and sometimes confusing.
The Type 99 project (also known as the ZTZ-99 and WZ-123) began in the late 80's after the Chinese government contracted Norinco to develop a third generation MBT. The tank was based loosely on the Russian T-72 with an elongated chassis and redesigned turret.
The classification for the tank was given as the Type 98. The Type 98 underwent trials over the next 10 years or so before being produced in very limited quantities for the 1999 Chinese National Day Parade where it was first exposed to civilian view.
Type 98 to Type 99?
There seems to be some confusion upon the release of Heng Long's two tanks, the ZTZ-99 and the ZTZ-99 (A). Some people have mentioned that the ZTZ-99 is actually a Type-98 and the ZTZ-99 (A) the correct tank.
It is a fairly understandable conclusion, however, one I believe to be incorrect. The 1999 Parade that premièred the Type-98 tank was not the end of the line for that tank. It was remarked that the tank did not go far enough to be on the same level as Western MBT's such as the Leopard or Abrams.
Further development of the Type-98 led to the Type-98 (G) which was then renamed as the Type-99 or ZTZ-99. As a project the Type-98 ceased to exist with all further development now on the re-designated Type-99.
The ZTZ-99 differs from the Type-98 is a few ways, it has a new and more powerful power plant. Up to date fire control and imaging systems as well as active defence.
I believe the first version, from information I have read points to be the Type-99 G, it wouldn't be the first time letter designations have gone awry in tank development.
Upon the A designation the tank received an armour upgrade in the form of composite or ERA (Explosive Reactive Armour) blocks. It is still undecided what the blocks are or if they are using the Russian method of ERA during combat operations and composite during peacetime and training.
I am also not sure of the turret changes where a rear bustle rack was added, it is possible the original A had side bustles only and ERA blocks over this and the A1 version had the rear bustle and extended armour.
An A2 version is apparently close to delivery and features a re-designed turret with a different armour package.