Great Frederick Chess

A systematic way to combine chess and draughts with a set of compound pieces with chess moves and draughts captures, including the contact captures of Fanorona.

But why?

Chess has en passant, where a pawn may be captured on a square it has passed over. But this only handles the edge case where opposing pawns are adjacent on the middle ranks. However, this is how capturing just works in draughts.

Great Frederick Chess

As a system rather than a specific variant, there is no limit on how large the game may be. However, it is in safe keeping with classical draughts rules for two player games to keep within 196 locations.
Compromise Between Draughts and Chess

In classical draughts rules, a sequence capture has to capture all the pieces in the sequence. The diversity of a Chess army obviates the need for this rule aided to a great extent by the presence of a royal piece. Thus it does not constrain the game too much to suppress them (virtually) altogether. Also, this royal piece is permitted to be physically captured in order to win the game.

To the advantage of the compound pieces, their draughts captures make it a natural rule that a player deprived of any further opportunity to play with them, including through promotion, has no right to win against one still having such.

The Two Divisions

Conservative: Add draughts doubletons to a classical variant, preferably all of the same type. They can gain Chess king moves on the back rank or according the promotion rules of the variant. It is practically better to add extra board space for them

Reform: fast and loose, see https://www.chess.com/clubs/forum/view/retry-at-getting-my-variant-idea-rated for examples

Ok