I've long been a bit nuts for hand-held chess technology...  Back in the 20th, I played so many games on my Novag Sapphire that I eventually blew out the LCD.  More recently, I got a Palm Z22 PDA exclusively as a hand-held chess computer.  Nowadays, however, my Z22 isn't seeing much action anymore - as my focus has turned increasingly to the growing selection of chess apps available for the iPhone and iPod Touch.

Truly, iPhone chess has blossomed over the past year or so.  Where there used to be only 1-2 very simplistic offerings, there are now dozens of chess apps - and an increasing number that are both high in quality and focused on the needs of more serious players and learners.  Thanks to the affordability of these apps, I've tried many of them...  Some have been deleted after a couple of hours, while others have become fixtures on the "chess pane" of my app library.

More than once, I've tried to name my "one true favourite" - but without much lasting success:  The best of the iPhone chess apps each have their own very individual merits, which keep me coming back to them for different reasons.  I could maybe tell you which are my top two or three, but it would probably be more fun to describe the attributes of each and let you decide.  To that end, I've described my six most-preferred apps below.  With confidence, I think they are collectively the elite of iPhone chess apps - making most of their peers in the App Store look like mere patzers.

Of course, the list reflects my own biases:

• First, I'm not too worried about the strength of the chess engines powering these apps.  They are all quite capable of kicking (my) butt and of giving helpful analysis.  If you do care, I'd guess that Hiarcs and Fritz are the toughest customers in the lot, but that's not based on anything terribly scientific.  
• Second, the list below favours apps that are, first-and-foremost, instructive computer opponents and analysis tools.  With one notable exception, I do not use iPhone apps to play chess with other carbon units.  So if you think this list is useless because I never once mention Chess with Friends, at least you were warned.  :-) 
• Third, I work in software for a living and I am passionate about elegant user-interface design and usability.  (Interface-design is a MUCH bigger deal to me than engine-strength, I assure you.)  If it's hard on the eyes or confusing, it's not here.

Ok...  Before shining a light on some of the interesting differences between these wonderful apps, here's a list of what you should generally expect from an iPhone chess opponent-&-mentor.  Unless otherwise noted, all of the apps described below include this basic feature-set:

• Play as White or Black, or computer vs. computer "auto-play"
• Two-player (or 'watch' or 'enter moves') mode - with or without analysis, the app simply allows you to enter moves for both sides.  (This feature is important not only to enable "pass-&-play" chess between two users, but also to allow you to use your iPhone as a casual game recorder.)
• Handicap features & levels (to weaken the computer's play for different player skills)
• Hint feature (note that in most cases, the hints are using the same level-setting as the engine's played moves - so if you are playing a handicapped difficulty level, you'll probably get likewise handicapped hints.)
• Position set-up features
• Switch sides during play
• "Coach" feature - this is a blunder-warning feature that can be turned on or off; as with 'hints' the coach is generally only as sharp as your configured handicap permits.
• Save game & load previously saved game (most apps allow you to save multiple games); also, remember current game when app is closed
• Email game (as PGN text)
• View computer analysis (some apps allow you to view the computer's thinking as you play; for others, analysis is visible only in a different 'mode')

Now on to the apps, in no particular order...  For each, I've included a link to the uQuery product page (nothing that will open iTunes, I promise), current pricing information, an overview, a list of 'best qualities' and of 'potential drawbacks.'  Of course, the drawbacks are 'potential' because not everyone will find fault with the same things I do.  :-)

Shredder   ($9.99)

At the high end of the pricing scale, Shredder nevertheless earns its keep, and has garnered very high ratings among its user-base.  One of the 'big name' chess software brands to enter the iPhone arena, this app is true to its pedigree:  The user-interface is simply excellent, it plays fantastic chess, and you get 1000 chess puzzles thrown into the bargain as a very nice bonus.

Shredder features an option to adapt its own strength to better match yours after each game, and it keeps a record of your rating and rank as you progress.  Add to this the ability to manually adjust the app's playing style, and Shredder makes for a very adaptable and rewarding opponent.  Shredder's analysis mode is nicely integrated and fun to watch.  There are a number of board/piece options to choose from, and they all look very smooth.

Blitz players may be disappointed that there are no clocks here, and learners will need to look elsewhere for guidance about openings theory.  [Edit (Dec 9):  The new version of Shredder announces opening names. :) ]

Best Qualities:
+  Attractive, logical user interface minimizes 'drilling' through multiple menus & screens to get what you want
+  One of few apps that will resign or consider a draw offer
+  1000 timed puzzles are included to help you hone your tactics
+  Shredder tracks both your rating and puzzle stats
+  After each game, the adaptive strength option can auto-adjust Shredder's playing strength to provide the perfect match for your level of skill
+  Graphical gauge shows at a glance Shredder's evaluation of who is ahead; it's great for openings experimentation or casual sparring, but can be turned off for a more serious game
+  Analysis feature is easy to access and includes graphical arrows on the board to show what the engine currently believes is the best next move

Potential Drawbacks:
-  No openings-book features for learners:  Shredder does not show book moves, opening names or ECO codes  [Edit:  Again, the new version does announce openings, by name and ECO code.]
-  No ability to configure time constraints for a game
-  Font for move list and analysis may require a bit of squinting for some, as it's quite small

[Edit (Dec. 18):  There is now a $.99 'Lite' version of Shredder in the store.  The engine is slightly weaker, and it has 100 puzzles instead of 1000.  You can't alter the engine's playing style.  It can't email games, and appears not to allow editing positions.  I'm unclear on whether or not it includes analysis mode.]

tChess Pro   ($7.99)

tChess Pro is an amazing little app.  "Little" only because it's the only app to weigh in at less than 1MB; it nevertheless sports some truly unique features in addition to the basics.  What marks this app most for me is its creativity and its focus on features for learners.  A good example of both, the "openings library" provides an excellent way to practise and learn about various openings as you play.

It's a good-looking app, especially if you like slick, dark-coloured themes, and the implementation of access to most-used features is, for the most part, excellent.  (For instance, whereas many apps force you to go back and forth through a game one move at a time, tChess can quickly expose the whole move list, and you can relocate simply by tapping the relevant move.)

The app is updated quite frequently, and has seen the addition of some excellent features in the time I've had it.  My favourite?  The very original "cut-&-paste" PGN feature, which nicely complements email export, providing a handy way to get a game IN to the app without having to manually enter every move.

(If you don't mind an engine that's about 700 Elo weaker and can live without some of the more advanced features, you can enjoy tChess Lite and save yourself $7.00.)

Best Qualities:
+  Extremely usable interface
+  Interactive "Learn Chess" course is built in for those new to the game (nice!)
+  Innovative openings-library features allow users to hand-pick a book opening at the beginning of a game, and also to view a break-down of commonly played move options (from a collection of master- and GM-level games) in a wide variety of opening lines
+  Unique "cut-&-paste game" feature allows you to easily 'import' (or export) games as PGN using your device's built-in clipboard
+  Only app that supports blindfold chess!
+  Option to view engine analysis during play
+  Wide variety of difficulty modes and settings:  Levels (1-12), Use available time, Fixed search time, & Fixed search depth
+  Rich time controls, including up to three time 'stages' (X moves in Y minutes, or Game in X minutes) with discrete Fischer increment options
+  Well integrated analysis mode - lines are readable and the thinking time per position is user configurable rather than infinite (to avoid undue drain on your battery)
+  Records detailed statistics about your performance against each level of difficulty (which can always be reset)
+  The lower handicap levels seem believably 'human,' and really do offer less experienced players a decent chance of winning once in a while

Potential Drawbacks:
-  If you don't like the board colours or piece set, too bad - they can't be changed
-  Engine strength at each level is not characterized in Elo points anywhere  [Update:  In ver. 1.5 levels have been replaced with Elo points - you can play a virtual opponent rated anywhere from 500 to 2500.]
-  You may need a treasure map to find the Resign and Offer Draw functions [Update:  They are easier to find now, but apply only to rated games - which are the only games that affect your profile statistics.]

Deep Green   ($7.99)

If iPhones came with a chess app "out of the box," I think it would look a lot like Deep Green.  No other chess app so effectively utilizes iPhone's potential as a game platform.  Beautiful graphics and original sound-effects complement other options like "call-outs" (small speech bubbles allowing the pieces themselves to announce "check," etc.), and create an engaging chess experience.

However, in its current version, the app still lacks some of the basic features sought after by serious chessers (see below).  There are plans to address these desires in a version 2, but so far, there is no ETA for that update.  One of the serious chess features that is most certainly NOT missing is a decent engine:  Deep Green plays to win.

Interestingly, Deep Green is the reincarnation of a popular, if short-lived, chess application that was originally written for the Apple Newton.

If you want a closer look at the super-model of iPhone chess, you could check out Deep Green Lite as a test drive.  It will cost you nothing and includes ALL the features of the full version - except the ability to remember where you are when the app restarts (so don't play if you're expecting a call).   :-)

Best Qualities:
+  The user interface is a work of art - no other app looks or sounds quite as polished.
+  The game-play experience is focused on pure fun - but without creating annoying distractions
+  Comprehensive help system
+  Nifty slider-based "play-back" mode
+  "Concentration" levels allow the program to make occasional human-like mistakes
+  A perfect app for casual play

Potential Drawbacks:
-  Although gorgeous "as is," the look-&-feel cannot be significantly changed via user options
-  No openings-book features for learners
-  No visible analysis or 'coach' (but does have a basic 'hint' feature)
-  No ability to save multiple games, or to export games by email

Hiarcs   ($9.99)

As a long-time fan of Hiarcs's Palm application, I eagerly anticipated its arrival on the iPhone.  And for the most part, I wasn't disappointed.  The engine is ridiculously strong; even the handicap levels seem stronger than they should be.  The app's opening book is best-in-class.  Better yet, the app can (optionally) show you its built-in book options to help you develop your own repertoire.  (It's not as interactive as the tChess openings library, but on the other hand, the Hiarcs book is quite a bit deeper.)  Moreover, like Shredder, Hiarcs has an adaptive strength feature that will assign you a performance-based rating and adjust its own strength to better match yours after each game.

Mind you, I didn't get everything I was hoping for with the first version of iHiarcs...  The Palm version is capable of handling games with multiple variation lines, a capability notably absent in the iPhone version.  I'm hopeful this will be added in a future release, as it would represent a much-desired first in the field of iPhone chess.

To be honest, I am also a bit underwhelmed by the Hiarcs interface - especially if you compare it to Shredder or tChess, which have similar feature-sets.  The piece sets here are a bit grainy and the board colours are too saturated for my taste.  I was also a little thrown to discover, for instance, that if you want the computer to move, hitting the button labeled "Move" is entirely the wrong approach.  Finally (and this may sound funny, I realize), the app moves too darn fast:  It's as though its responses are practically simultaneous with my own moves.  Am I supposed to be intimidated by this, or what?  :-)

Anyway, certain quirks and undocumented behaviours do take some getting used to, but Hiarcs is a power-house and a great option, especially for advanced players.

Best Qualities:
+  Choose to display a variety of move-options (with evaluations of "!" and "?") from the app's very deep opening book as you play - once the game is out of book, the options are replaced by the opening's name and ECO code
+  Difficulty is easily set to match a skill "class" or a particular Elo score
+  Similar to Shredder, has an "Adapt Strength" feature that adjusts the engine strength after each game, based on your performance to date
+  Very configurable engine - allows user to configure playing style (Solid, Active, Aggressive) and opening-book variety (Off, Wild, Surprise, Dynamic, Tournament)
+  Option to view engine analysis during play
+  Wide variety of chess-clock pre-sets for blitz and rapid games (up to game-in-30-minutes with a 5-second delay)

Potential Drawbacks:
-  User interface is a bit less polished than in other apps, particular at this price point
-  Clock settings are not manually configurable - pre-sets only

(By the way, if you want to get a 'feel' for the Hiarcs interface - or if you just want to enjoy a very robust, and completely free, chess app for serious players - check out Glaurung.  Although there are many particular differences, much of the look-and-feel aspect of Hiarcs derives directly from Glaurung.  Incidentally, by rights, Glaurung probably deserves its own spot on this list - simply because it's a whole lotta chess app for no money.  The truth is simply that I don't use it much since getting Hiarcs.)

Fritz   ($6.99)
Weighing in at over 18MB (more than twice the size of Hiarcs, the next largest app on this list), Fritz for iPhone is not exactly lean, but it's definitely mean.

Gammick Entertainment licensed the engine from Chessbase and have also used it in Fritz versions for game console systems like the Wii.  The fact that the iPhone version shares a certain design vision by these console versions has perhaps resulted in a user interface that is just a bit much.  Of course, other users may differ.  In any case, I take particular exception to the sound effects, and the less said about the built-in "music" options, the better.

Still, it's a generally good-looking app that includes most of the information you would want to see at a glance (captured pieces, clocks, etc.).  The configurable Help system can also indicate threats, which may be helpful for those new to chess.  However, there is no 'Coach' feature in the current version.

The engine strength can be configured to one of 11 different levels, represented in Elo points from 400 ("Novice") up to 2320 ("Grand master").  You can also configure whether the engine will resign or accept draws relatively early, relatively late, or never.  You can also configure the clocks for a "Blitz" or "Long" game, or play with unlimited time.

At any point, you can jump to the "Analyse Game" screen which allows you to review the game move-by-move, as Fritz displays and constantly re-calculates a single line of analysis.

If you want a glossy interface and a very strong opponent, Fritz provides good value for $3.00 less than Shredder or Hiarcs.

Best Qualities:

+  The user interface?
+  "Show Threat" feature to help newer players stay out of trouble
+  As you play, graphical arrows can indicate the most common book moves in the opening

Potential Drawbacks:
-  The user interface?  :-)
-  The "coach" feature may be missed by some users

Chess.com   ($0.00)

The recently-introduced Chess.com app is a bit of an odd choice for my list, since it is arguably the only app mentioned so far where vs-computer play is not the main focus of the app.  However, it does include a flexible computer opponent and a highly configurable, attractive interface.

But the chess.com folks didn't stop there.  There are four major parts to the app:  computer play, online correspondence chess, a tactics training regimen, and even a library of instructional videos that can be viewed right on your device.  For the record, you really need a membership at Chess.com to enjoy the full benefits of the other (non-computer-play) features, but with a basic registration (which costs nothing and can be done quickly through the app), you have computer play and unlimited correspondence chess against other Chess.com members (some 750 000 of them).

Oh, and I almost forgot to emphasize this:  the app is completely free.

So to keep things somewhat fair, let's just forget all that ".com" stuff and focus on the "Play Computer" aspect.  Once again, this a good-looking app - cosmetically about on par with Shredder, and with an even greater range of options (9 boards x 9 piece sets).  Feature-wise, the computer opponent provides all of the usual capabilities, including a nicely integrated view of the computer's thinking (if desired) and different clock options - all in all, a pretty amazing product, seeing as they're giving it away.

Best Qualities:
+  Integrated analysis view
+  High-quality, very configurable look-and-feel
+  Select engine playing style, from “Passive” to “Suicidal”
+  A wealth of other learning tools & online play against other users (membership has its benefits!)

Potential Drawbacks:
-  Version 1.0 still has a few kinks, but they should be resolved very shortly
-  Configuring difficulty may seem a bit simplistic to some:  In addition to the playing style configuration, there are ten straightforward levels - simply numbered 1 through 10.  There is no reference to Elo or rank equivalents here.


Well, there you go - those are my "big six."  There are some other apps out there I respect almost as well as these - Glaurung (strong & free), Chess Genius (showing its age, but still the only app that can download PGN databases from the Internet) being two of the most noteworthy.  And where would I be without ChessQuest and Chess Problems, the two best dedicated tactics apps in the Store??... But I digress.

I'd say that as far as iPhone chess opponents are concerned, the perfect app has yet to be written.  When that day comes, I'm sure the app will have Hiarcs's brawn, tChess's thoughtfulness & Deep Green's good looks.  It will support annotation and variation lines.  It will analyze my games, inserting natural-language advice and then emailing me the results.  The in-game coach will speak to me directly, using the voice of Stephen Fry or Cate Blanchett (user option).  It will make mistakes I can take advantage of only by improving my own tactics.  It will have a sense of humour.

Until that day, I'm happy I've got the chess team described above in my back pocket.  I hope this has been somewhat useful in choosing one or more partners of your own.  I apologize in advance if I've neglected a great app or been unfair in my representation of the ones above.  Feel free to yell at me in the Comments.

Cheers!

PS.  If you liked that post, you should check out this group.