Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bb5/3...a6/4. Ba4/4...b5

=Morphy Defence, Caro Variation= Black puts pressure on the bishop. /5. Bb3/ is the only available move.

Theory table
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 * 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4. Ba4 b5