This blog entry is in response to a Openings Forum topic I saw a few days ago, appropriately entitled "Why the Philidor's". The topic author, who had enjoyed overwhelming success against this opening couldn't understand why black would even bother to essay it. Since I play the Phildor's on and off, I was happy to see others reply, ensuring the topic author it was indeed viable in the hands of a prepared black player.
For the record, I wanted to consolidate the practical points for black rolling out the Philidor's Defence, from someone who plays it with some degree of regularity.
Practical Point #1: Diversity
Within the Philidor, black can adopt one of at least four different approaches to the position, depending on his style:
Practical Point #2: Frequency
To me, there's nothing more frustrating than putting time into an opening that I don't get into frequently enough to justify. If you're playing either of the Hanham variants, the desired position can be reached through the move order of 1. e4 d6 2. d4 Nf6 3. Nc3 e5, to be followed by ...Nbd7. Of course, one has to be prepared for the endgame resulting from 4. de de 5. Qd8+ Kd8, but this has been shown to have no teeth for white. Against weaker players, black can avoid this equalizing queen trade by playing 3...Nbd7 and only then following up with 4...e5. The alternate move order mentioned here avoids King's Gambit, Scotch, Vienna Game and other openings that black would otherwise have to study for.
The 1...d6 move order can also be deployed against 1. d4, where black can hope for 2. e4 to steer the game back into Philidor waters.
Practical Point #3: Stability
Although currently being played at the highest levels, theory on the Philidor is still relatively slow to change. Thus, compared to other defences such as the French or Sicilian, the lines and ideas are not nearly as volatile. The trade-off is that some of the lines, such as Philidor Counter-Gambit and Larsen's Variation can lead to inferior positions with theoretical best play. But how often are your opponent's faced with these lines to warrant keeping up the latest "best play". Meanwhile, along those paths, there are numerous traps they have to avoid.
Practical Point #4: Economy
With the Hanham and Lion variations, as with a number of other black replies to 1.e4, they almost fall into the category of set-ups since the black's moves are almost the same regardless of white's continuations. Naturally, this makes them easier for black to play as he should develop a "feel" for these positions.
Of course, this contrasts with PCG and Larsen's variation positions which tend to be quite sharp, so in those cases specific moves and order are quite important.
As mentioned earlier, if coupled with a repertoire replying to 1.d4 with 1...d6, playing the Philidor can lead to great economy. For instance, when playing against higher-rated players, there is absolutely nothing wrong with replying 1. d4 d6 2. e4 with 2...e5, daring white to enter a queenless middle-game even better for black than the one resulting from 1.e4 d6 2. d4 Nf6 3. Nc3 e5 4. de de 5. Qxd8+ Kxd8.
Of course the question then becomes "what happens after 1. d4 d6 and white DOESN'T cooperate with 2. e4?". Fortunately 1...d6 is perfectly viable against 1. d4 and may already fit in with your 1. d4 defense if you play, for instance, the King's Indian, Old Indian, or Leningrad Dutch. If you don't play any of these and might be in the market for some new ideas against 1. d4, then I highly recommend "An Explosive Chess Opening Repertoire for Black", a very good book (although I'm not sure how any repertoire featuring 1...d6 could be characterized as "explosive"). The book is currently out of print, however there are a few used copies available on Amazon.com, and your local chess book seller may have it as well. The authors of this book recommend the Pirc against 1. e4, while only later in the writing does Philidor transposition occur to them. Ironically, today, 1.e4 d6 is the most frequent way high-level players obtain the Philidor Hanham position. This order avoids 1. e4 e5 2. Nf3 d6 3. d4, where 3...Nbd7 is playable if looking to steer towards a Lion, but can lead to inferior versions of the standard Hanham. Of course, if black is looking to play a PCG or Larsen's Philidor, then by all means the 1. e5 is completely appropriate. 