Error in Lesson

The lesson, "Essentials of Opening Play" contains an error concerning the Ruy Lopez. It states, While 4.Ba4 is a good move, 4.Bxc6 is more common and is also very strong.

This assertion is wrong. Not only is 4.Ba4 vastly more common, it is generally considered a better move. It certainly scores better for White (see image below).

The Exchange variation, which is advocated in the lesson, has its merits, but it is not the most popular, as stated. It also is not the best variation for teaching the concept of the opening.

I was reviewing lessons for beginning players because some of my students have asked about Chess Mentor. Do I need to tell them to steer clear of the courses on openings?

Given that the statement in question is at the end of a very long paragraph, which your students probably aren't going to bother reading, I don't think it much matters. They're just going to click that "Free Move" button and move on. You're right of course though that in the author's enthusiasm for teaching the exchange variation, he plays fast and loose with the facts.  Chances of it being corrected ?  Not good.  At least not until the current V3 crisis is resolved.

The good news is that CM errors are pretty rare, at least in the newer courses, although I certainly haven't tried them all.  Good catch though.

In the free samples, there is another lesson with almost the same name. It offers the main line as the main line.

These internal inconsistencies are interesting.

There's another "error" that I noticed yesterday, but a more complex one.

In the Chess Mentor Demo (http://www.chess.com/chessmentor/view_course?id=28), the dem010 lesson (Spassky-Petrosian 1969) lesson seems quite good. However, this evaluation changes if you compare the opinion offered of the first move in the lesson (the move played in the game, and based on the themes of the lesson) to Garry Kasparov's view of that move (My Great Predecessors, part III, p. 289).

It would be nice if there was a way to discuss these lessons akin to the discussion feature of Tactics Trainer.

Hello, I'm new here, so can't start a new topic.

In a lesson "Pawn Tension is Your Friend" I moved a pawn b4 making a bishop to go Be7. I think it's not the best move, as it can take a pawn ... Bxb4! and after cxb4 a queen can move ... Qxb4 threating a knight, a bishop and a rook.

Which doesn't lead anywhere:

21. Bxd7+ Kxd7

22. Bd2

Agree with you, but it's an alternative to a bishop defence Be7. Because black can probably use a rook on Rb8, however I'm unsure it's a good attack.