Variation
A variation is one branch of an opening, defined by a move or sequence that differs from another continuation.
A named variation belongs to a broader opening, but the term is also used for unnamed alternate lines in analysis. After 3.Bb5 in the Ruy Lopez, 3...a6 and 3...Nf6 lead to the Morphy and Berlin defenses.
One position can lead to several variations
A variation is one continuation from a position where more than one move has been studied. Some branches have established names. Others are simply alternate lines within the same opening.
This is easy to see in the Ruy Lopez position after 1.e4 e5 2.Nf3 Nc6 3.Bb5. Black can choose among several named defenses from the same board position.
Play one of Black's four marked replies to see which variation it begins.
Play one of Black's four marked replies to see which variation it begins.
A variation can branch again
After 3...a6 selects the Morphy Defense, White faces another decision. The bishop can capture on c6 for the Exchange Variation or retreat to a4, where the game can enter a Closed Ruy Lopez setup.
Opening names describe different depths of the same tree. The word after the colon in a database may be called a variation, defense, attack, gambit, or system, but each name still identifies a branch reached by particular moves.
| Level | Example | Defining moves |
|---|---|---|
| Opening | Ruy Lopez | 1.e4 e5 2.Nf3 Nc6 3.Bb5 |
| Variation | Morphy Defense | 3...a6 |
| Subvariation | Exchange Variation | 4.Bxc6 |
Starting position · Position 0/8
In PGN, variation can also mean an alternate line
Chess players also use variation for an analyzed sequence that may not have a formal opening name. PGN stores this kind of alternate line as a recursive annotation variation, or RAV, inside parentheses.
The line in parentheses starts from the position before the move it replaces. In the example below, 1...c5 is an alternative to 1...e5, so both replies branch from the position after 1.e4.
1. e4 e5 (1... c5 2. Nf3 d6) 2. Nf3 Nc6(1... c5)- This branch returns to the position after 1.e4 and replaces Black's first reply.