OK, I want to try my hand at designing a really large chess-like variant too. The goal is to distinguish it from other variants that use a massive army on a large board by typically having shorter games. For this purpose it implements some features that I have been lobbying for to accelerate a game: flying pieces that put the King at risk even in the stage where it still hides behind a massive army, and some very destructive pieces that are subject to an anti-trading rule, to longer preserve the offensive power of the armies:

• Eagle, Falcon and Bat are 'flying pieces' (moving as Q, R, B): they can jump over arbitrary many pieces in their path for checking or capturing.
• They cannot jump over each other, though, and can also not jump over the (low-valued) Archer or a Spearman. All these pieces can capture each other, even when jumping.
• The Terrors move and capture like a Queen, but can also perform hit-and-run capture, by making an extra step (forward or backward) along the same ray to an empty square after they capture.
• Terrors cannot capture each other, unless the attacking Terror is completely safe afterwards (like it was a King).
• Pawns and Warriors promote upon reaching last rank, to Eagle, Amazon or Griffon.
• Fast castling can be used to move a King to the wings.
• Pawns can initially slide 2 or 3 steps forward to an empty square.

I post this as a comment before submitting it as an article because the design is still tentative, and I hope to get some feedback. I am for instance not very happy with the inclusion of the Steward. It is so much like a Pawn. But I did want a weak (but interesting) piece. Perhaps I should use a Checkers King instead (mFcafmF)?

The concept of flying pieces emulates a two-level board (ground and sky), where a ground battle is conducted on a densely populated board in parallel with an aerial battle on a thinly populated board, and air-to-surface strikes are always possible, but only a few units are capable of shooting down aireal targets.

Some of the ideas on which I based the design:

Most of the pieces I used belong to the set of 'more intuitive' fairy pieces that also feature in the family of 'Cazaux variants'. I supplemented those with the Terrors and the flying pieces, tailored for their job as 'game accelerators'.

I tried to keep close to the 'value spectum' of orthodox Chess, where a next-lower value class has double the number of pieces. So I have 30 Pawn-class pieces (Pawn, Warrior, Steward, Grasshopper), 24 minors (Knight, Bishop, Camel, Zebra, Elephant, War Machine, Cannon, Vao, Prince, Frog, Archer, Spearman), 12 Rook-class pieces (Rook, Nightrider, Dragon Horse, Dragon King, Leo) 6 Queen-class pieces (Archbishop, Marshall, Queen, Griffon, Rhino, Lion) 1 Amazon. The flying pieces would probably be Queen class or higher, and the 2 Terrors would top everything.

I did include Nightriders, which are a bit less intuitive. But after all, "The night is dark, and full of Terrors!".

Compared to orthodox setups massive armies tend to be relatively short on Pawns. This brings the risk of the Pawns getting exterminated in the heat of battle, before the board population has thinned enough for them to promote. The game then would become slow (or even drawish) for lack of promotable pieces, which are the main 'amplifiers' for an otherwise non-decisive advantage. I tried to cure that by including the Warriors as a 'second wave' of promotable pieces.

I did want to preserve the principle of 'passed Pawns', and thus avoid Berolinas and other Pawn types that can easily change file. So the Warrior can only non-capture straight ahead, but it can slide two squares in this direction on any rank. This extra speed is of no use, though, as long as there still is a normal Pawn in front of the Warrior, obstructing it.

To prevent building of an almost impenetrable double wall of pawn-like pieces, the Warriors have no normal capture. They can check and e.p. capture like a normal Pawn.

As other pieces in the lowest value class I included Grasshoppers. But to prevent forking threats in the opening I severely limited their range.

The flying pieces can be used to shelter the King and other valuable pieces from flying attack. But they need to be able to shelter from such attack by lower-valued flying pieces themselves. For this purpose the two most exotic minors (Archer and Spearman) were given the power to block flying pieces.

In the initial setup the most-valuable ('noble') pieces shelter behind a wall of flying pieces. The latter again shelter behind Archers and Spearmen, or a relatively low-valued Leo, which would counter-attack the source of any flying attack over it.

Diagonal flying attacks that go behind this shield can only come from an area that is so close by that is can be easily controlled (by Pawns or Elephant).

All Pawns are protected in the initial setup.

The rank behind the Pawns does not contain any noble pieces. So threats from pieces that could reach there (Nightrider, Cannon) need not be feared.

The minors are placed on 4th rank such that they don't compete too much for a place to develop them on 6th rank.

The pieces that are present in only a single copy, and thus necessarily cause asymmetry in the setup, were all placed in the central 4x2 area around the King.

Since the Eagle is upward compatible with all flying pieces and hoppers, and the Amazon with most other pieces, it did not seem very useful to allow promotion to other pieces. But perhaps I should allow promotion to any non-royal, just for simplicity.