Open, Skipworth Gambit

After 6. Re1, Black props up the attacked knight with 6...d5 instead of the standard 6...Nc5. This keeps the extra pawn for now, but it opens the diagonal toward the uncastled king. White can check at once with 7. Bxc6+, an engine favorite, or play 7. d3 to undermine the e4 knight. The most direct option, 7. Nxe5, regains the pawn. Engines give White a large advantage, and White scores heavily in the few games played.