As for the mention in the last paragraph that 'details will be found on a later page', this refers to the material I covered in More on Castling in Chess.
At first I was afraid that my book was to be sheer plagiarism. But I was encouraged by the discovery that if you steal your ideas from one author, that is plagiarism; whereas if you lift them from many, that is research.
If he were alive today, Davidson would undoubtedly be a keen blogger.
Murray described the King's Leap in separate sections in his chapter on 'The Mediaeval Game'. One section addressed chess in Spain, another addressed chess in Italy. Here's what he had to say about the Spanish game (p.457-461).
In fact, except for point (4) in the second part, most of the material I've excerpted has nothing to do with the King's Leap. I've left in the rest to establish the period covered, to show Murray's own sources (MS. Alf. is the Alfonso manuscript and is well described on other Web pages), and to overview the rules of the pre-modern game at that time, particularly the Queen, the Bishop, and the Queen's leap.
The King's Leap. It occurred to early chess players that if in actual practice a mounted soldier could escape capture by leaping over his enemy, the King, who presumably would also be mounted, could escape in the same way. The King was surely as potent as one of his own Knights. And so there was introduced in Sanskrit chess the King's leap -- a privilege of moving like a Knight. This is still the rule in the Malay peninsula where once during the game (usually when "checkmated" -- or to escape checkmate) the King may leap like a Knight. [...] An initial two-move leap for the King was permitted in European chess down to the 13th century.
For more about Davidson, see The Origin of the Initial Position and More on the Initial Position. In his chapter on the Rook, he tied the leap to castling (p.48):
Castling. The root of castling is the King's leap [described above]. There were two forms of this leap. In the first, the King could jump once like a Knight. In the other, he had the privilege of going two squares on his first move. The latter form of the "King's leap" was the practice in European chess down to the 13th century.
In the North African variety of Arabic chess, the King was put into a safe corner by a two-stage procedure. First he moved into the second rank. Then the Rook was brought into the King's original square and simultaneously the King went to the Rook's corner. This was the embryo of modern castling and its development from there proceeded along logical lines. [...]
From North Africa [castling] crossed the Mediterranean along the trade routes and its first appearance in Europe was in Italy toward the close of the 15th century. For a while, Italy was the only country in Europe which used castling in chess play. As the Arabic crescent waxed around North Africa and crossed Gibraltar, the chess practices of the Moslems entered Spain and in the 16th century castling was the rule in Spanish chess. By this time, however, the Arabs had consolidated the maneuver into a single move, so that one-move castling was practiced on the Iberian peninsula and two-move castling on the Italian peninsula.
By 1630 castling was known in France, Britain, and Germany, though because of its dual ancestry, there was for a while some confusion as to the technic. [...] By the end of the 17th century, castling in the modern manner was a fixed rule of chess.
Davidson had a tendency to explain historical facts by speculative musings (e.g. 'It occurred to early chess players...' above). I've removed most of these from the quotes I selected.
Note the frequent mention of the word 'leap', a rule that was a carryover from the precursors of modern chess. I'll cover that in another post.
Murray believed the rule for modern castling arose from the necessity to standardize the rules as players from different localities travelled to compete with each other in an 'even contest'. From his 'History of Chess' (p.811):
I've left the points about stalemate and en passant in the excerpt because Murray's four points are his complete account of the local differences in chess in the 16th century. It was also easier to leave them in than to take them out!
Davidson speculated that the three flank pieces occupy their positions (RNBxxBNR) because that is the most efficient arrangement for an army. Murray, on the other hand, was not so sure ('History of Chess', p.46):
To emphasize Murray's central idea: 'There is no obvious reason why the remaining pieces should be arranged in any particular way, and the existing arrangement (RNB) was probably only arrived at after experiment'. In A Database of Chess960 Start Positions, I pointed out that there are only twelve symmetrical positions with the King and Queen in the center. Of these, there are six with the King on e1 and the Queen on d1.
SP323 • BNRQKRNB
SP326 • NRBQKBRN
SP332 • NBRQKRBN
SP515 • BRNQKNRB
SP518 • RNBQKBNR
SP524 • RBNQKNBR
The move of the modern Bishop wasn't developed until the late 1400s, and could not have been a factor in chaturanga. Experience with chess960, however, shows that when the Bishops start in the four corners, they are often exchanged quickly. I made another observation which might be relevant in Undefended Pawns in Chess960 Start Positions.
Taking SP518 (RNBQKBNR), the eight Pawns are defended in a pattern that looks like 1-1-1-4-4-1-1-1; the a/b/c and f/g/h Pawns are all defended exactly once, while the d/e Pawns are each defended four times. This symmetric result for SP518 is partly because the King and Queen protect the same number of Pawns from a particular start square. It turns out that there is only one other SP that has the same start profile as SP518, its 'twin' SP534 (RNBKQBNR), where the King and Queen swap places on the central squares.
Another variant, which is not a legal start position in chess960, is what Murray called a crosswise arrangement. This is where the King and Queen (or her equivalent) start not on the same file, but where the King starts on the same file as the opposing Queen. This arrangement is seen in certain oriental chess variants. Has it been tried in modern chess?
[For a general discussion about the evolution of chess from chaturanga to the modern game, see The Origin of Chess.]
***
Later: Re the 'crosswise arrangement', on p.360 Murray gives the moves for a complete game where the Kings start on e1 and d8. White castles Kg1 and Re1; Black castles Kb8 and Rd8.
From Murray's 'History of Chess' (p.27; in the third line, the 'same conclusion' is that chess was first developed in India):
From Davidson's, 'A Short History of Chess' (p.7):
Sanskrit Chess. When the game first entered the pages of history, it was called chaturanga and was played in western India. Than, as now, the board was made up of 64 squres, eight by eight. The chessmen represented an Indian army and the name was derived from a Sanskrit word for 'army'. Chaturanga literally means 'four arms'. Chatur is Sanskrit for 'four' and is the ancestor of the Latin word quattor (visible in such English words as 'quartet'). The other half of the term, anga, meant 'arms', and it was in military Sanskrit precisely as we use it in military English. Thus we speak of the 'arms' of the service, meaning its components, such as infantry, cavalry, artillery, and so forth. These are the 'arms' (the very word 'army' has the same origin). The old Indian army was composed of four 'arms': chariots, elephants, cavalry, and infantry; and the word chaturanga meant 'the four arms', that is, the army as a whole.
In the battle line of the Sanskrit army, the chariots were posted on the flanks, while the king and his prime minister stationed themselves in the protected and important center of the line. The cavalry were also deployed on the flanks but nearer the center to permit fast wheeling-in movements. The lumbering elephants were stationed just off center. This is the traditional battle line of all armies -- and for that matter, of a football team, too. Speed on the flanks, power in the center. Finally the foot soldiers were ranked in the front line, then, as now, bearing the brunt of battle. Thus chaturanga was an effigy of a battle.
A little later, Davidson explained that the elephant was the ancestor of the Bishop. The title page of his book tells us that he was a 'Major, Medical Corps Reserve, United States Army', thereby putting his remarks into context.
The conclusion of both authors is that the initial position has carried over virtually unchanged from the 7th century A.D. Murray, however, gave no explanation for the sequence of the three pieces on the flanks. I'll come back to that point in another post.
