Chess 1999 combines rules from Chinese Chess and western Chess while adding many new rules to create a game representing modern warfare.  Following is an explanation of why certain rules are used.

 Playing Board

The playing board represents the grid coordinate system on a military topographic map.  Each square represents one kilometer.
Some military symbology is used on the board.

 Movement

Infantry battalions represent light infantry battalions.  Movement is derived from the pawn in Chinese Chess.

APCs represent regular infantry (or mechanized infantry) battalions.  Personnel carriers can move at higher speeds than men on foot so the APC moves up to two kilometers.

Howitzers represent artillery batteries.  Movement is based on the movement of the cannon in Chinese Chess.  Jumping is required to simulate the range of artillery fire and that the artillery pieces are not visible to potential targets.

The general represents the theater commander.  He is confined to the CP because without proper equipment for communication and intelligence evaluation battlefield command and control is lost.  Movement is a blend of the movement of kings in Chinese Chess and western Chess.

Fighter jets (F 15 and MIG 29) represent fighter wings.  They have a long striking distance and excellent maneuverability.  Movement is based on the chariot in Chinese Chess and the rook in western Chess.

MRLs represent a variety of SSM (surface to surface missiles) and SAM (surface to air missile) batteries.  They may strike a variety of points from great distances.  A jump is allowed for the same reason as the jump for howitzers.  Movement is somewhat related to that of the elephant in Chinese Chess.

Bombers (B1 Stealth) represent bomber wings.  They are very powerful strategic or long range weapons but lack maneuverability at close range.  Movement is based on a limited queen in western Chess.

Attack helicopters (Apache and HIND) represent helicopter wings.  They are powerful tactical or short range weapons.  Movement is based on a limited queen in western Chess.

Tanks (M1 Abrams and T80) represent tank battalions.  Movement is similar to that of a horse in Chinese Chess.

Guards represent security measures at the CP.  Guards may not leave their posts unless properly relieved.  Thus the guard must stay at the CP.  Movement is the same as that of guards in Chinese Chess.

Special Rules

CP:  The CP allows more movement because it is located in an area with good roads and has all the accouterments of a semi permanent military post.

Infantry capture:  It is assumed that pieces taken are usually destroyed in the process however infantry troops occasionally take equipment intact.  This equipment can be channeled to special forces operations.

Promotions:  While promotions may seem rare to a front line private, they do happen at times. So why not?

Checkmate:  When the command and control element crumbles so does logistics and the effectiveness of your force.