Shock Troops

Shock Troops or ST Chess is a variant that uses the standard 8x8 board, and normal chess pieces set up in the standard configuration. During play each side has the option instead of making a regular move or to drop one of two pieces into any vacant space in the back rank.
The two pieces introduced this way are the War Knight and the Elephant Knight.

The War Knight makes either an orthogonal step or leaps 2 squares horizontally or vertically. Similarly, the Elephant Knight makes either a diagonal step or leaps 2 squares diagonally.
In addition to their unique moves, both pieces can also move like regular knights. They capture by displacement like any other piece.

Setup

	Shock Troops Start position One War Knight and One Elephant Knight to be dropped in empty space from a1-h1 for White or a8-h8 for Black 2 Ninja Pawns to be dropped (and optionally moved) in empty space from a2-h2 for White and a7-h7 for Black.

Pieces

Movement:
The ninja pawn can always move 1 square up or 1 square sideways to an empty square regardless of where it is situated on the board. It can also make an initial double step just like the regular pawn.

Capture:
Like the standard pawn it can capture one square diagonally up, regardless of which half of the board it is on.
When the ninja pawn is on the top half of board (White rank 5 or greater +, Black rank 4 or less) , it can also capture one square horizontally.

There is no en passant. It cannot capture another pawn or ninja pawn en passant nor can any other pawn capture it this way.

Promotion: The ninja pawn promotes on the last row, to any piece. Promotion to a piece is mandatory so it would cease to be a pawn in the last row.

The War Knight and Elephant Knight are compounds of ancient very well known elements: the Ferz, Alfil, Warmachine, and Wazir. They were also used in Grand Shatranj under different names.

Sub Variants

There are a number of sub-variants using this system. A very interesting sub-variant involves the War Drone and Elephant, which both move exactly like the War Knight and Elephant Knight respectively, minus the knight movement. This reduces the power on the board and might be a preferred variant for some players.

Of course, if the ninja pawns are not to everyone's taste, both sides can play without them.

Another interesting variant is to use the Chancellor and Archbishop instead. Note that this would make it very similar to Seirawan Chess especially if used without ninja pawns, but with a more logical dropping mechanism.

Rules

A piece from the reserve can be dropped in empty space of back rank during a turn. The drop takes up a move and no piece can be moved on the same turn.

Ninja Pawns are dropped unto an empty space on the second rank. They can be optionally pushed forward on the same turn.

Notes

Such considerations as when the pieces should be allowed to enter the game require a lot of play testing and feedback. It is clear that it is more flexible to allow them to enter at any time, and there does not seem to be any valid reason to limit the dropping to the initial stages of the game.

I had to, however, demonstrate that the use of slightly less powerful but still formidable jumpers as a very viable and possibly superior alternative to the Seirawan Chess setup. Not to mention the use of ninja pawns, which adds a subtle change to the gameplay.

So despite my enthusiasm for this variant and my other variants as well, I have come to realize that chess - the standard 8x8 type - may well be the most fascinating game of all. It seems to have even gained in popularity a bit in recent years.

Nonetheless, the exploration of different board sizes and new pieces is entirely justified and must continue. For who knows what lies within these parallel universes! All that is required is a substantial amount of testing, play and research within any one of these new systems, and an entire new faction of chess can flourish.