It seems that we can make many comparisons between chess and cycling grand tours. The way that I see this, is that a stage represents a move in chess, and the term of the stage can vary depending on whether we take it from our move, or our opponents. Below are some examples:
Rook - is the obvious ITT piece. Traditionally comes into play late in the game.
Castling - is the ITT that is surprisingly added earlier in the race. This can be viewed as a Rook stage or a King Stage. For example, it is a Rook stage for Bavarianrider, but a King stage for Airstream.
Pawns - generally speaking these are the flat stages for the sprinters, or sprinter, in the case of Cav. You may also want to change the spelling of this piece in some instances, for the piece always seems to do the same boring thing and in the end the outcome is always the same (a Cav win), leaving us feeling rather empty and needing to restock.
Occasionally one of these flat stages results in a crash which impacts the race. This is when the pawn takes a piece.
The pawn can also reflect on a prologue or early TTT, since pawns can move two squares on their first move.
Knights - can also move to start the game (though this is more of a defensive move), so therefore can also be a prologue or TTT. Is a piece that can be both positive and negative, so it's stages can surprise in both ways. Could also be related to the cobble stages as it would be a good idea to take a horse with you on difficult terrain.
Bishops - tend to look like a mini-Queen, and so the stages also act as such. These stages also take shape when their are crosswinds, as was cleverly pointed out earlier.
Queen and King - obvious.
2012 Tour De France: As seen (and played) through the eyes of Andy Schleck (forgive me on the early stages, can't remember what the parcours is exactly).
Prologue: Knight stage.
Stage 1: Pawn stage.
Stage 2: Bishop stage.
Stage 3: Pawn stage.
Stage 4: Pawn stage (piece taken).
Stage 5: Knight stage.
Stage 6: Pawn stage.
Stage 7: Bishop stage: Andy puts on a show of power up the short MTF, apparently demonstrating that he is the strongest climber in this Contadorless Tour De France. Although his time gains were minimal, Andy proceeded to make outrageous claims to the press that the race was over. "I am the best, quite clearly, and would be even if that Spanish s..t was here. And just take a look at the cavalry I have alongside of me (insert evil laugh here). I don't see the point in us carrying on like this for another two weeks. And by the way, what was the deal with having a half decisive stage before the final week. That I certainly hadn't expected." Yes, Andy's bishop stood very proudly errect after this stage....
Stage 8: Knight stage: Andy enjoys a splendid gallop through the medium mountains. To his delight it was quite an uneventful day.
Stage 9: Castling (King) stage: Andy's plans are all thrown out of whack during a disappointing day against the clock. "But Johan said that this would all be easy. And I had planned on all my attacks for here, and now, I really don't know what to do. Damn the French and their bloody castles!"
Stage 10: Pawn stage: Andy does very little bar play with himself, still upset over the recent King stage.
Stage 11: Queen stage: Andy shows grand aggression, and suddenly things are looking up again.
Stage 12: Pawn stage.
Stage 13: Pawn stage.
Stage 14: King stage: Andy was feeling good about his game again, and was planning another wonderful move with his Queen (he attacks on the major climb of the day), but suddenly he finds himself under fierce pressure (the entire peleton is bearing down on him in the LONG run in to the finish) and has to surrender and move his King. "They encouraged me to dance, so I got my groove on, and then the DJ turns the f..k..g music off! What a pathetic party today was!"
Stage 15: Pawn stage.
Stage 16: Knight stage: Andy had wanted to experiment with his Queen again (looking good and drops numerous riders on the Perysourde), but many reduced their deficits on the descent. Always remember that Knights are less effective later in the game....
Stage 17: Bishop stage: Yet again a Queen move was planned, but things just weren't going Andy's way, and the game didn't offer him any room to move (the Queen). All he could do was make a rather passive Bishop move, and his gains were limited.
Stage 18: King stage: "For f..ks sake. Where are the real mountains?"
Stage 19: Rook stage.
Stage 20: Pawn stage: Opponent reaches end of the board.
Check Mate
