This is not some new or obscure chess opening variation. Instead the Janus Variation is the generic term I have invented for a certain category of variation which will differ from one player to another and which may take a different form over time for each individual player. This kind of variation is hardly ever discussed in chess openings books – in fact I have only seen it mentioned once, long ago, and I can’t remember which book that was.

Confused? You won’t be. Read on. But first, an explanation of the name of this variation, for those of you without a classical education. In the religion and mythology of Ancient Rome, Janus was the god of beginnings and endings among other things. The month January is named after him (one year ends and another one starts). He is usually depicted as having two faces, each of which looks in the opposite direction.

When you think about the opening in chess, what naturally comes to mind are your chosen openings for either colour. For example I currently play the English Opening as White. My main Black defences are the Sicilian Sveshnikov vs 1.e4, and the QP Slav vs 1.d4. Actually I play a wide range of openings and these are just my current favourites.

It is a fact of chess that there is always one opening you have to play as both White and Black. This will be obvious if you ask yourself, What do I do if my opponent plays my favourite opening against me? Suppose you play 1.d4 as White and the King’s Indian Defence as Black. When you face the King’s Indian Defence as White, you play the Classical Variation with Nf3 and Be2. What do you do as Black if someone plays the King’s Indian Classical Variation against you? It doesn’t matter exactly what you play. At some point, you have to play the same line with either colour. This is what I mean by the Janus Variation. You have to look both ways.

I said that the content of the Janus Variation may differ for each individual player over time. Until recently I was playing 1.e4 as White and the Sicilian Najdorf as Black. Against the Najdorf I would play the highly-theoretical 6.Bg5 main line. So I had to be prepared to play that line as Black as well. Nowadays the Janus Variation has changed for me and I have to know the positions arising from 1.c4 c6 for both sides.

What should be the characteristics of the Janus Variation? Obviously it has to be playable for both sides. It should result in middlegame positions which offer chances to both players and which you would be happy to play as either side. Learning an opening for both sides is a good way to improve because you have to understand the typical plans and positions for both sides. This leads you towards a consideration of the best moves. It’s no good playing a trappy but inferior continuation for one side if you know how to refute it from the other side.

In my case, from my 1.e4 and Najdorf days, I have a copy of every recent and important opening work on the Najdorf for both sides, and I also have the relevant Chessable courses for both sides. I’d like to think that my understanding of this opening, and my ability to play it properly, has improved as a result.

The trend in openings books does not lend itself to this kind of study. Many years ago, openings books tended to examine the opening objectively and recommend the best play for both sides with comprehensive coverage of all lines. Sometimes these were reduced to tables of opening variations with analysis of each line and an evaluation at the end of it. Think Modern Chess Openings (MCO), 15th edition by Nick de Firmian, published 2009, or Nunn’s Chess Openings (NCO), published 1999, with the Good Doctor leading a team of openings experts.

Over time, repertoire books have become much more common. These present an opening from the point of view of either White or Black. It must be what players want these days. So for example The Iron English by Simon Williams analyses the Botvinnik Variation of the English for White (the setup with c4, Nc3, d3, e4, g3, Bg2, Nge2, 0-0) and considers everything Black might play against it. If you’re looking for something Black might play against the English, and in particular against non-Botvinnik lines, this is not the book for you. I’m not saying anything against this very popular repertoire book, which is as engaging and thorough as the man himself. I’m just making the point that it’s written from one point of view.

Where it gets interesting is when the same author produces a book on the same opening for first one colour and then the other. For example take the Keep It Simple series by IM Christof Sielicki. In Keep It Simple for Black, originally a Chessable course then published in book form by New In Chess in 2022, he recommends the Caro-Kann as Black’s main defence to 1.e4. Against the Exchange Variation he analyses a setup with …Nc6, …Nf6 and …e5, often resulting in positions where Black has an isolated d-pawn. He also has some useful things to say about the “Carlsbad” pawn structure arising from the Exchange, typically where Black doesn’t play …e5 but keeps the position closed, where White has the half-open e-file and Black has the half-open c-file, and he outlines the main plans for both sides.

Then, around the end of 2022, Sielicki publishes the Chessable course Keep It Simple for White 2.0, an update on the original course published a few years previously. In the original course, Sielicki recommends the Two Knights’ Variation against the Caro-Kann (1.e4 c6 2.Nc3 d5 3.Nf3). For version 2.0, he changes course and recommends… the Exchange Variation! So here he has to present the same opening from White’s point of view that he recently presented from Black’s point of view. Sielicki is honest enough to recognise the difficulty and points out that the positions are playable for both sides. Let’s take the position arising after 1.e4 c6 2.d4 d5 3.exd5 cxd5 4.Bd3 Nc6 5.c3 Nf6 6.h3 (6.Nf3 prevents …e5 but allows …Bg4 pinning the knight) 6…e5 7.dxe5 Nxe5 8.Nf3 Nxd3+ 9.Qxd3 Bd6 10.0-0 0-0.

Sielicki goes on to say: “The move 11.Be3, now my suggestion for White, is not mentioned in KIS Black, as I focused more on the direct attempts to pressure Black. Our strategy with White is a slow grind, trying to keep Black’s pieces passive and making slight progress. I think that chances are equal, but White’s job is quite easy, and it is not every Caro player’s forte to defend IQP positions.”

I’m not sure where that leaves Black supporters of the Caro-Kann. What are they supposed to play against the Exchange Variation? I guess we’ll have to wait for Keep It Simple for Black 2.0 to find out.