Chess Opening Theory/1. e4/1...e6/2. d4/2...d5/3. Nc3/3...Bb4/4. e5/4...c5/5. a3/5...Bxc3

=French Defence, Winawer Variation= Black takes the pinned knight to avoid having his bishop boxed in. White's only plausible reply is 6.bxc3.