According to the book from Beginner to Expert in 40 lessons, in the 10th century, the bishop like the knight could
jump over other pieces in a diagonal line, BUT must move ONLY and EXACTLY two squares. As “Fischer Random” has
become “in vogue” why not the idea of “ancient rules chess”
Rob Jones
People still play chaturanga, and there have been several books devoted to chess variants. Bill Smythe has posted on several of them, when he’s not busy creating help-not-mates and such. 
A cute little variant on chess that older kids seem to enjoy is the “rule” game. A third person comes up with a special “rule” and the others play chess (as best they can) without knowing the special rule. The rulemaker intervenes when necessary to prohibit moves, take pieces off the board, or whatever to enforce the rules. For instance, a rule which says that a piece which moves to a square where it is neither guarded nor attacked is lost, so 1 e4 results in the e pawn being removed. 1 d4 is OK since the Queen guards it. 1 d4 e5 is OK (e5 is attacked), then 2 dxe5 results in both pawns being lost… (That actually makes for interesting “chess” if you know the rule; it can be rather weird when you don’t).
Both of my sons are into games, and one card game they like to play is one where there are rules in place and the object of the game is to figure out what they are.
But anything beyond Dilbert is too much work for me. When they bring out the Settlers of Catan box, I go read a book.
The 10th century rules lasted until at least 1475. The new rules (our rules) caught on principally because the vizier went from being the weakest piece to the strongest piece, as the renamed queen.
There were two other reasons the new rules became popular. One is that you could play it with the same board and pieces. In many other variants you need a new piece or pieces, e.g. a combination rook and knight.
The other reason? To play well under the old rules you needed to know an elaborate series of moves to start the game, a tabiya.
In other words, the new rules got rid of centuries of opening theory.
How about Fissure Random Rules? (I spelled Fissure differently to avoid confusion.) Instead of randomizing the initial position, you randomize which “extra” rule (from a list of 30 or so pre-given possible extra rules) is in effect. First to guess correctly what the extra rule is wins the game. An incorrect guess immediately loses.
Of course, you’d need to have a 3rd party (preferably a computer) to referee the game, as in Kriegspiel.
Bill Smythe
Colonel Mustard, with the lead pipe, in the Library.
The vizier becoming the queen was (pardon the expression) a real game-changer. Games became shorter, and tactics became important almost from the first move. Opening theory as we know it dates from then; there wasn’t much opening theory before then, because the game was so slow, and what there was became irrelevant.
This is all according to H.J.R. Murray’s book, A History of Chess. He indicates that the “new” chess replaced the “old” chess all over Europe almost as fast as it could be carried; that is, it reached some countries later than others, but in every country, it took only a generation to replace the old chess. So, you could try teaching people about ancient rules chess, but I doubt that it would get much traction.
If one wants to play correspondence Shatranj and doesn’t mind doing a trial on schemingmind.com to do so, feel free to message or challenge me there (btphartford). It’s pretty cool, in a non-cool way.
Is shatranj the game that shows up in the Noah Gordon book, The Physician? I’ve never decided if he gives all the rules for that game, so I’m not sure what he was using as a reference.
Well, try it on schemingmind.com, and see if you can guess the rules. 
Bill Smythe