27 April 2017

Annotated Game #173: I like the London System

For whatever reason, I've traditionally had good results (as Black) in London System type games.  It's quite popular now for White and certainly offers good development and play.  On the Black side, I've found it to be not as challenging as other White systems in the opening phase, essentially because less direct pressure is placed on Black, so I feel like I can equalize and then play a comfortable game.

The below tournament game follows this pattern, with me equalizing as Black by move 6 and having some easy ideas to follow in the middlegame.  By move 18 the position is drawish, but I chose to be patient, as I felt any (slight) chances would lie on my side.  I was able to target the one weakness in White's position (the b2 pawn), but then my opponent cannily fought back to create an unusual endgame fight (2N+R vs my two rooks).  I did have an outside passed pawn, though, which ended up being decisive, after some interesting tactics (see move 36).

This game isn't of very high quality - too many dubious (?!) choices on both sides - but was valuable to analyze, including identifying a thinking process lapse (move 23, where I could have consolidated my advantage if I had recognized my opponent's best response).

Class C - ChessAdmin

Result: 0-1

[...] 1.d4 d5 2.¥f4 evidently going for a London System type setup. 2...¤f6 3.¤f3 c6 4.e3 ¥g4 (4...¥f5 is a standard alternative.)
4...£b6!? may be a little premature, but it hits at White's queenside immediately, now that the dark-square bishop is away. Kramnik once gave it a try against Gata Kamsky: 5.£c1 ¥f5 6.c4 e6 7.¤c3 ¤bd7 8.c5 £d8 9.¥e2 ¥e7 10.h3 ¤e4 11.O-O g5 12.¥e5 ¤xe5 13.¤xe5 ¥f6 14.¤xe4 ¥xe4 15.£c3 ¥g7 16.b4 O-O 17.b5 cxb5 18.¥xb5 £c7 19.¦ac1 f6 20.¤d7 ¦fd8 21.c6 bxc6 22.£xc6 £xc6 23.¥xc6 ¦ac8 24.¥b5 ¥g6 25.¤c5 ¦d6 26.a4 ¥f8 27.¤a6 ¦c2 28.¦xc2 ¥xc2 29.¤c5 e5 30.¦c1 ¥f5 31.g4 ¥g6 32.¤d7 ¥e8 33.¤xf8 ¥xb5 34.axb5 ¢xf8 35.dxe5 fxe5 36.¦c7 d4 37.exd4 exd4 38.¢f1 d3 39.¢e1 ¦d5 40.¦xa7 ¦xb5 41.¦xh7 ¦b1+ 42.¢d2 ¦f1 43.¢xd3 ¦xf2 44.¢e4 ¦f4+ 45.¢e5 ¦f3 46.¢e6 ¢g8 47.¦h5 ¢f8 48.¦xg5 ¦xh3 49.¢f6 ¦a3 50.¢g6 ¢g8 1/2-1/2 (50) Kamsky,G (2671)-Kramnik,V (2729) Turin 2006
5.c4 e6 6.a3 this takes away the b4 square from Black, but is a rather slow approach, neglecting piece development. 6...¥d6 a natural developing move that challenges White's strong Bf4. 7.¥g3 O-O 8.¥e2 not bad, but not optimal. It also prompts me to play the next move. 8...dxc4 while not really a full tempo loss for White, it's still annoying to move the bishop twice in a row. For Black, the benefit is to re-establish the pin on the Nf3 and achieve a solid central pawn formation that restricts White's light-square bishop. 9.¥xc4 ¥xg3 the exchange of bishops is more or less obligatory at some point, given the tension on the diagonal. I thought this was a good time to do it and enable the subsequent pawn break. 10.hxg3 c5 challenging White's central pawn outpost. If White is takes the c5 pawn, having the king in the center after a queen exchange on d1 would be worth the sacrifice, plus the pawn is recoverable. 11.¥e2
11.dxc5 £xd1+ 12.¢xd1 ¦c8 13.¤c3 (13.b4?!13...a5 14.bxa5 ¦xa5³) 13...¦xc5 14.¥e2
11...¤bd7 with White preparing to castle, now the pawn is better off being protected. 12.O-O ¦c8 13.¤bd2 cxd4 exchanging the pawns opens the c-file and reduces White's central pawn formation. 14.¤xd4 ¥xe2 15.£xe2 ¤b6 the idea being to challenge control of c4 and give the option of hopping to d5. 16.¦ac1 £d5 the queen is now nicely centralized, but White lacks any weaknesses that it could attack. 17.£f3 a6 taking away a useful square (b5) from the Nd4, in anticipation of the exchange. 18.£xd5 ¤fxd5 the position now looks very drawish and the engine agrees. In the past, I've been impatient with such types of positions and might even have offered a draw. Now I treat such situations more as learning experiences and will not on principle offer a draw until a position is truly played out (or perhaps if I assess I am worse off). 19.¤2f3 a minor slip by my opponent. With my next move, I now have a slight edge and am creating threats. (19.¤e4!?) 19...¤a4 20.¦fe1? (20.b3 ¤ac3 21.¦c2 ¦c7 22.¦fc1 ¦fc8 23.¢f1 ¢f8) 20...¤db6?! played as the result of not fully calculating the capture on b2. I thought that White could get the pawn back easily with Rb1, so took the step to screen the b7 pawn with the other knight first.
20...¤xb2 21.¦b1 originally I stopped calculating here, just seeing the threat to the unprotected b7 pawn. 21...¤d3 a nice intermediate move threatening the Re1 and now 22.¦ed1?
22.¦f1 is best but after 22...b5−⁠+ Black is winning with a mobilized 2-1 queenside pawn majority.
22...¤c3−⁠+
21.¢h2 however, my opponent now gives me an extra tempo to execute the threat. 21...¤xb2 22.¦b1 ¤2a4µ23.¦b4 ¦c3?! here I didn't pay enough attention to my opponent's possible ideas, just going for the a3 pawn. (23...¦c4µ) 24.¦eb1 at this point I saw that he will get back some material. 24...¦xa3 25.¦xb6 ¤xb6 26.¦xb6 h6 right idea, but wrong timing, according to the engine. White could now play g4 and activate the king via g3. (26...¦a5 would be better, keeping the rook more active.) (26...¦a2 would also be good.) 27.¦xb7 we now have an interesting, dynamically balanced endgame. If White had two bishops instead of two knights I would certainly be in worse shape. I still have to watch out for attacking ideas for White that use his two minor pieces and rook in combination, but my passed a-pawn and rook activity mean that the position is equal. At this point I didn't know if I could win, but I felt that at least I could avoid losing. 27...¦a2 28.¢g1 ¦c8? too aggressive, neglecting the weak f7 square. 29.¦b1?! missing the threat he could make aginst f7, at least for now.
29.¤e5 h5 cutting off the exit square for the White king 30.g4 hxg4 31.¤xf7 ¦c5± looks rather ugly for Black.
29...a5 passed pawns must be pushed! 30.¤e5 ¦c7 now I am thinking more about defense. 31.¢f1 a waste of a tempo. 31...a4³ White isn't lost yet, but the initiative is with me now and the a-pawn keeps getting stronger. It's also hard to find the specific continuation for White that holds. 32.¦e1?
32.¦b8+ (playing Kg1 first is also fine) 32...¢h7 33.¢g1³ is the key according to the engine, which is rather hard for humans to see. White's king needs to get off the first rank, where it can be checked with tempo gain by a rook to facilitate the queening of the a-pawn.
32...a3µ33.¤d3 ¦d7?! right file, wrong rook. (33...¦d2!34.¤b4 a2−⁠+) 34.¤b4? after this I find a winning continuation. (34.¦d1³) 34...¦b2−⁠+35.¤dc2 a2 36.¦a1 this seemed to be an excellent defense and I spent a good deal of time coming up with the game continuation (which is the best according to Komodo). I had originally spotted the idea of the tactic ...Rb1+, which now doesn't work to break through. 36...¦d2
36...¦b1+ 37.¢e2 ¦xa1 38.¤xa1−⁠+ is still winning for Black, but with a lot more work to do.
37.¢g1 but now the ...Rb1+ tactic does work! (37.¦xa2 ¦xa2 38.¤xa2 ¦xc2−⁠+) 37...¦b1+ 38.¢h2 ¦dd1 the most effective continuation, now with a double attack on the Ra1 and on the h1 square threatening mate. 39.g4 ¦xa1 40.¤xa1 ¦xa1 41.¢g3 ¢f8 42.¢f4 ¢e8 43.¢e4 ¢d7 44.¢e5 White's king cannot venture onto the d-file without suffering a rook check, with the a-pawn then queening. 44...¢c7 45.f4 ¢b6 with the simple winning idea of threatening to chase away the knight, which will force its exchange for the a-pawn. 46.g5 hxg5 47.fxg5 ¢b5 48.¤xa2 ¦xa2 49.g6 fxg6 50.¢xe6 ¦xg2 at this point White cannot win and at worst I'll end up with K+R vs. K (an elementary mate). 51.e4 ¢c6 52.e5 ¦g5 53.¢f7 ¦xe5 54.¢xg7 g5 now there is no way of stopping the pawn from queening and making the Q+R vs. K mate very obvious. My opponent however was a junior who apparently didn't realize the etiquette of resigning when you are in such a situation. 55.¢f6 ¢d5 56.¢g6 g4 57.¢f6 g3 58.¢g6 g2 59.¢g7 g1=£+ 60.¢f6 £f1+ 61.¢g7 ¦e2 62.¢g6 ¦g2+ 63.¢h6 £h1#
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23 April 2017

Annotated Game #172: Light and Dark

This next tournament game is probably the best one of mine that illustrates the idea of weak-square complexes and how one can exploit them, which for Class players is a sometimes mysterious concept.  Here we have a clear light vs. dark situation on the board, with my opponent's pawns placed on dark squares, which have the effect of restricting his dark-square bishop, but more importantly leaving open the light squares to be dominated by my pieces.  This situation was evident by move 17 and demonstrated by the effectiveness of my centralized knight (these weaknesses aren't just for bishops to exploit).

Although even well into the middlegame my opponent either had a small advantage or at least equality, despite his weaknesses, I felt comfortable playing the position and was able to identify good ideas for making progress.  I also correctly identified many of the important positional ideas (including strong and weak squares) and found dynamic moves like the (temporary) pawn sacrifice idea on move 19.  The turning point of the game was the sequence that began on move 23, which involved my finding some unexpected intermediate moves and placed my opponent under significant pressure for the first time; this led him to err with 26...Rf7?!  Although not a losing move in itself, I was subsequently able to maintain the initiative for the rest of the game and win an interesting, dynamic minor piece endgame.  Even considering some weaker play in the opening and early middlegame, I feel this game serves to highlight some of the signposts of progress that I have been making in strengthening my game.

ChessAdmin - Class C

Result: 1-0

[...] 1.c4 c5 2.¤f3 ¤f6 3.¤c3 ¤c6 Symmetrical Four Knights variation. 4.g3 e6 indicating my opponent is going to take a relatively cautious approach to the opening, at least early on. 5.¥g2 ¥e7 6.O-O O-O 7.d3 I thought for a while here on the best approach to take. The main alternative is d4 (and by far most often played), while b3 is also a possibility, with a double fianchetto position. 7...d5 8.cxd5 played to reduce Black's central pawn presence and make pressure from the Bg2 down the long diagonal more meaningful. 8...exd5 9.¥g5 in the English it's sometimes hard to know what to do with the dark-square bishop. I didn't see a future for it on the queenside and on f4 it could be harrassed by ...Nh5, so I picked g5. When playing this move, White has to be prepared to exchange it for the Nf6, so evaluating the effects of that piece trade is important. 9...d4 10.¥xf6 I had foreseen Black's last and considered that the resulting position was good for me, with the centralized knight vs. a locked-in Bf6. 10...¥xf6 11.¤e4 ¥e7³ objectively speaking, Black is a little better here. He has the two bishops and a small space advantage. That said, the position is relatively easy for me to play, with some clear ideas for making progress. 12.¦c1 done in the expectation of provoking Black's next move, which opens up the long diagonal for the Bg2. 12...b6 13.¤ed2 while the knight looked good in e4, it had no squares other than d2 open and could therefore be threatened by ...f5 (which Black plays shortly). Redeploying it gives it an equally good square and improves my piece coordination, is what I thought. 13...¦b8 my opponent appears concerned about the rook on the open long diagonal, so moves it. 14.a4 with the idea of preserving the c4 square for the knight, by restricting the ...b5 advance.
14.¤c4!? can in fact be played immediately to good effect. For example 14...b5?!15.¤fe5 taking advantage of the hanging Nc6 and the R+Q fork on the square. 15...¤xe5 16.¤xe5 ¥b7 17.¤c6 ¥xc6 18.¥xc6
14.a3!? would take away b4 from the Nc6, which is helpful in several variations.
14...f5 I felt that this move now was too loosening for Black's kingside. The knight is prevented from returning to e4, and the pawn then continues to f4 to try to weaken White's kingside pawn shield, but that does not appear to be sufficient reason for Black to weaken the a2-f8 diagonal and the light squares in general. (14...¥g4!?) 15.¤c4 f4 16.¤fe5 now my other knight gets into the action and releases the Bg2's power. 16...¤xe5?!
16...¤b4 is a significantly better choice, giving the knight an excellent outpost on b4.
17.¤xe5 the Ne5 now eyes the weak c6 square. I had thought that if Black exchanged the light-squared bishop for the knight (for example after trying ...Bb7, which I was thinking of following by playing the Nc6 fork) then that would leave me with a significantly positive imbalance between the remaining minor pieces (my light-square vs. Black's dark-square bishop). 17...£d6 the best option for Black, removing the queen from the fork and centralizing it.
17...¥b7? would in fact have been a significant blunder, but for other reasons: 18.£b3+!18...¢h8 19.¤f7+ ¦xf7 20.£xf7+⁠−
18.¤c6 now an exchange is not forced, but the Nc6 still causes Black difficulties. 18...¦b7 19.b4 I felt that this was necessary to energize my position and use my pieces most effectively, particularly the Rc1 (which is not otherwise playing). Komodo agrees. 19...¦c7 Black passes up the (temporary) pawn sacrifice.
19...cxb4?!20.¦c4 I had spotted this idea, targeting Black's weak pawns on the 4th rank. 20...fxg3 21.hxg3 ¥f6 22.¤xb4² and White has a slight advantage due to better piece activity.
20.bxc5 bxc5 now the position is still equal, but I have nice pressure against the c-pawn and comfortable play on the queenside. 21.¤a5 fxg3 it's often difficult to decide which pawn recapture to make in this situation. I decided that the open f-file would benefit me more than Black, who does not have his rooks connected on the back rank, and that the resulting pawn formation would be a bit more solid, not offering Black any prospects of an attack down the h-file. The drawback of the text move, as I immediately realized, was that I lose control of the e3 square, so I had to watch that carefully. (The engine gives an assessment of equality to both pawn recaptures, incidentally). 22.fxg3 ¥g5 here my opponent evidently did not consider the intermediate moves I could play in response to the threat against the Rc1, which end up giving me the initiative. I felt this justified my decision to open the f-file. 23.£b3+ ¥e6 24.¦xf8+ forcing the recapture with the king, as the Be6 otherwise would be left undefended (deflection tactic against the Qd6). 24...¢xf8 25.£b8+ placing the queen on the back rank and pinning the Rc7. 25...£d8 my opponent thought for some time here and found the best reply. (25...¥c8?26.¦f1+ ¥f6 27.¥b7±) 26.¦f1+ ¦f7?! this allows me to win the a-pawn. (26...¢g8) 27.¦xf7+ ¥xf7 28.£xa7 Black has some compensation in the form of the two bishops heading into the endgame, so I only have a small advantage. When calculating the pawn capture, I also needed to be very careful about evaluating Black's next move, which is very trappy. 28...¥e3+ I had thought a good deal about this position prior to initiating the previous sequence, so was prepared. 29.¢h1 better than f1, although it gives the king no squares. Either way is fine for White, however, according to the engine. 29...£e7 30.£xe7+ at the time I was happy to enter the endgame with the advantage of a passed a-pawn, although I figured that combating the two bishops could make it a hard slog. At least with the queens off, I did not have to worry about mating threats. The engine evaluates keeping the queens on as significantly better for White, since the queen can more effectively shepherd the a-pawn forward. However, queen endgames are also very complex, so I think I made a decent practical decision in trading material. 30...¢xe7 31.¤c6+ ¢d6 32.a5 I had calculated this out prior to the knight move, as Black does not have sufficient time to capture the knight before the pawn queens. The idea is to block the Bf7 from getting over to defend, while the Be3 is also out of the action on the queenside. Now Black has to find an "only move" at this point to defend. 32...¥e8? a reasonable try, but not sufficient.
32...c4 is the only move that preserves equality for Black and is not necessarily easy to find (for humans). 33.dxc4
33.a6 c3 34.¤b4 ¢c5 35.a7 ¢xb4 36.a8=£ c2 as White cannot keep the pawn from queening. For example 37.£b8+ (37.£f8+ ¢c3 38.£xf7 c1=£+) 37...¢c3 38.£c7+ ¢d2
33...¥xc4 34.¥f3
33.a6 ¢c7 34.a7 by this point I knew that I would have to give up the a-pawn for Black's d-pawn, but was not sure when would be best. After some thought, I figured that it would be better to have Black's king a little further away. The engine disagrees.
34.¤xd4 makes the knight a much more threatening piece and introduces some tactical ideas. 34...¢b6 35.¤f5 ¥d4 I had seen this far and didn't consider it any better than the game continuation, but after 36.¤xd4 cxd4 37.¥b7+⁠− White has the easy winning strategy of activating his king and clearing away Black's d-pawn.
34...¢b7 35.¤xd4+ transforming the advantage of the passed a-pawn, by taking advantage of the discovered check. An example of a tactical trade, in this case the a-pawn for the d-pawn. 35...¢xa7 36.¤f5 ¥d4 I felt at the time that this was a losing move, giving away the benefits of the two bishops and clarifying my advantage. The engine is less harsh in its evaluation, not seeing the evaluation as any worse, although from a practical standpoint it made my mental task easier. 37.¤xd4 cxd4 38.¥e4 I thought for a while about this or Bd5, they are both good centralization moves. Since it provokes Black's next (unforced) error, I'm glad I went with it. 38...g6?+⁠− Now Black has made his kingside pawns vulnerable to penetration by my king and/or bishop. This was the actual losing move. (38...h6±) 39.¢g2 ¢b6 40.¢f3 the plan is very obvious for White here, to threaten the d4-pawn and tie Black's king to its defense, then go after the kingside pawns. 40...¢c5 41.¢f4 h6 42.h4 guarding g5 against a supported Black pawn advance 42...¥f7 43.¢e5 g5 44.hxg5 hxg5 45.g4 played as a prophylactic move, to keep Black's bishop from h5. 45...¥b3 with the idea of moving to d1. 46.¥f3 the safest route to victory. Now that Black can only move the king or bishop, eventually he will be put in zugzwang; my bishop protects both e2 and g4 and the king has full freedom. 46...¥d1 47.¢e4 I did this rather than move directly to e5 to have Black essentially lose a tempo with the bishop, although it's not truly necessary. 47...¥b3 48.¢f5 ¢b4 49.¢xg5 ¢c3 50.¢f4
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20 April 2017

How do you know you are becoming a stronger chess player?


Chess strength is a funny thing.  It's hard to define precisely, so we rely on rating systems (primarily Elo-based) as a proxy statistic for it.  Yet clearly there must be something substantive behind the explanation for why players have particular levels of strength, so we can talk about things like "master" and "expert" versus "Class B" and "Class C" players.  (I am currently a Class B player, per the USCF scale above.)

There are some helpful, if not necessarily definitive, attempts at providing "roadmaps" or the like to chess knowledge at each level.  Here is one posted at Chesstempo.  You can also infer what knowledge is considered standard to have at beginner, intermediate and expert levels from resources such as the Chess.com study plans.  Another approach is defining specific characteristics and skills that set the higher levels apart from others, as done by GM Andy Soltis in What it Takes to Become a Chess Master.  Soltis' book I think gets at some crucial concepts, including how masters are able to much better understand (and apply) things like compensation for sacrificed material in the absence of concrete winning tactics.  This includes "positional" sacrifices of the exchange or a pawn or two, where there is no combination on the board, yet the master understands that in the long term, their chances are better (or at least as good) as before the sacrifice.

All of the above approaches to explaining playing strength have their uses, but one of the conundrums of chess strength is that it often does not reflect the extent of a player's knowledge, at least on a one-to-one basis.  Some things are directly correlated with your ability to win; knowing basic mates and mating patterns are fundamental to success.  Others are helpful, but not 100% required (for example how to play the Philidor and Lucena ending positions).  Finally, some pieces of chess knowledge have a very low (yet non-zero) percentage chance of ever being directly helpful (such as knowing the K+B+N v K mate).  Soltis' work outlining particular crucial areas of skill I think comes closer to a cognitive approach, rather than simply giving a list of "must knows", but of course this approach is necessarily subjective, rather than rigorously scientific.

Similar to Soltis' approach, but on a more practical level for the improving Class player, I'd like to document some phenomena that appear as concrete indicators of improving chess strength.  It's not an exhaustive list, but I think it is useful to share.  I make no claim to having originated any of these ideas, but in reading widely and through analyzing my own games I have been struck by how important some of these are when they appear, and I have personally experienced all of them at one time or another.  Naturally there are many more improvements yet to come...

I've arranged the below phenomena in what seems to me to be a logical progression from ones based on more concrete/tactical/conscious considerations, to those that are more cognitive/strategic/unconscious in nature.  Again, these are meant to be taken as positive signposts you may see on the road to mastery, whenever you observe them in your games.  I think it's important for improving players to explicitly recognize the positives in their game, along with the many errors and negatives, otherwise chess can start becoming toxic and demotivational.  We (including professional players) will always fall short of perfection, but that's to be expected, and therefore not overly lamented.
  • I hesitate to start with this one because of its obviousness, but blunders (making less of them) really is fundamental.  If you keep having the same frequency of game-ending blunders (i.e. losing a piece or overlooking mating threats) over time, then by definition you will make little progress.  Having at least a basic blundercheck thinking process is necessary; over time, it hopefully will become more and more unconscious (but still necessary).  One practical observation I've read before, and tend to agree with based on personal observation, is that by Class B level the majority of games are no longer decided by blunders, and by Class A only a very few are.  In other words, you more often have to beat your opponent, rather than just waiting for them to beat themselves.
  • When analyzing your games, you have an increasing number of "!" annotations.  This is related to the above indicator on blunders (the "?" moves), but it is not simply the elimination of errors, but rather a demonstrable ability to find the key (sometimes only) move that gives you a breakthrough in the position.  You can always give yourself a "!" if you're feeling generous, but it's worth more when coming from an unbiased annotator, which in many cases will mean your computer engine.  Although there are some pitfalls of computer analysis, engines can almost always correctly identify the standout strong moves ("!") as well as the blunders.
  • Something a little less obvious, but a definite sign of improvement in strength and sophistication, is spotting and deliberately using intermediate moves when conceiving and calculating move sequences.  One thing I have seen repeatedly in my game analyses is that I (or my opponent) often may have a good idea, but it is not executed to the full extent of its power, whether it may be a strategic pawn break or a particular tactic that becomes much more effective with the insertion of an intermediate move.  I think that learning how to keep searching for more effective moves after finding a good idea is the key, including taking a particular idea and then looking creatively at the different possibilities of how and when it could be most effectively played.  Annotated Game #171 has some good examples of effective intermediate moves.
  • As part of your evaluation of the position, you start naturally "thinking in squares" rather than just about the pieces and threats to them.  Weak squares in your opponent's camp become magnets for tactical and strategic ideas; one common example is if f2/f7 become underprotected next to a castled king.  Excellent squares should also suggest themselves (see below) for your pieces - for example leading to the repositioning of a knight, perhaps even using a tactic, to get it to a dominating outpost on the opponent's side of the board.  Defending your own weak squares and realizing when they might be created (after a pawn push, when a key piece moves away) is also very important, the more so the higher level you get.  (See this example commentary game.)  Going back to the thinking process, Botvinnik suggested thinking on your opponent's time about positional considerations rather than calculating variations - squares are a big part of this process.
  • Allied to the automatic recognition of "thinking in squares" is the development of a more automatic/unconscious visualization skill, in other words the ability to picture future board positions in your mind.  I have found that this grows naturally in the context of a consistently applied training/study plan, as long as you sometimes move the pieces in your head rather than always on the board.  One good example of doing this is when variations are given in an annotated game and you visualize them, rather than playing them out physically.  This can also be practiced in reading chess books without a board, starting with ones that have plentiful diagrams (such as Logical Chess: Move by Move).  At a basic level, you should not need to have the board coordinates (A-H, 1-8) printed on the board for you to immediately identify a square.  The next stage is being able to mentally picture (away from a board) the color of a particular square (d4 is black, b7 is white, etc.) quickly; if you can't do this, then your internal board sight is not functioning on an unconscious level and the need to process this consciously will slow you down.  Finally, being able to play a game "blindfold" (without sight of the board, whether or not you actually are wearing a blindfold) is more than a parlor trick, it is a sign that you have strong visualization skills that will strengthen your calculation and evaluation of variations.  Blindfold chess skill is again not a one-to-one correspondence with overall chess skill - not everyone can be Timur Gareev and he is not at the super-GM level (yet) - but it is a strong indicator of your general strength level.
  • While the above are largely conscious mental efforts related to the process of calculation - with visualization being, I would argue, also a partially unconscious function - one unconscious-origin phenomenon is when a move "suggests itself" without you doing any calculation at all.  At a certain level this phenomenon is related to what we call "natural moves" - which to a lower strength player do not necessarily appear natural at all.  Geometrically these can typically be defined as when an individual piece can be moved to a square where it will have maximum influence across the board, particularly into the opponent's camp.  More sophisticated versions of this idea occur when we have a mental library of successful positional patterns built up, so we make an instant comparison to what we have seen work before.  To quote Magnus Carlsen: "Of course, analysis can sometimes give more accurate results than intuition but usually it’s just a lot of work. I normally do what my intuition tells me to do. Most of the time spent thinking is just to double-check." 
  • Finally is an observation that I once read by a GM (the source regrettably does not occur to me right now, maybe Yermolinsky?) who noted that when you gain strength you do not in fact feel any stronger yourself; rather, your opponents start seeming weaker (in the same Elo range as you).  This is naturally a largely unconscious impression, but I believe it's a valid one and probably one of the most powerful indicators that you have in fact shifted significantly past a previous milestone in chess strength.