Ampel Variation

The Ampel Variation is an eccentric sideline of the Zukertort Opening. White answers 1...d5 with 2. Rg1, shifting the king's rook onto the square the knight has just vacated. The move develops nothing new and spends a tempo. It also gives up the right to castle kingside, although the rook on g1 could later support a g2-g4 advance. There is no established theory behind it. Black, unhindered, can occupy the center and develop normally.