How bad is 1. e4 c5 2. Nf3 d6 3. a3? Is this move clearly losing for white? Chessgames.com shows 1 win and 2 losses for white only, and I could not find any other reference for this move.
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 1. e4 c5 2. Nf3 d6 3. a3?


No, it is not clearly losing, but I would say that the question mark is appropriate. You have to understand that white, by the nature of going first, can afford to waste a move in many early opening positions without it being a losing move. What it does though is it usually throws away any chance at gaining an advantage, and that is because you cannot be sure that the wasted move, in this case 3.a3?, will be helpful to your position as the position develops. In general, in the opening, you want to play moves that you KNOW will help you and that you know you want to play...you cannot know that about a3. a3 also does nothing to fight for the center. At best, you might play an early b4 trying to get play in the Wing Gambit.

In the Mega Database, there are actually 35 games, but the average rating for white and black is only 1796 to 1768, so that should tell you a lot: Strong players do not think it is good, even if not losing. For the record, white only scores a 37.1% with 3.a3?, but again, anything can happen between 1700s.