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New CT-ART 5.0 combines three excellent courses guiding you from beginner to advanced level. » ChessOK Aquarium Basic

ChessOK Aquarium Basic: Cutting-Edge Analysis Tools Powered by Rybka 2.2n2

Deep Rybka 3 Aquarium logotype ChessOK Aquarium Basic – revolutionary analysis and database tool, combined with the world’s strongest freeware chess playing engine, Rybka 2.2n2.

Aquarium offers advanced analysis functions, game commenting, searching, powerful chess trees, playing, databases and much more.
ChessOK Aquarium Basic Screenshot (click to enlarge)

Powerful Analysis Methods

ChessOK Aquarium Basic Screenshot IDeA (Interactive Deep Analysis) is a new, unique and powerful analysis method. IDeA examines a position and then follows the most important moves automatically to create a tree of variations. It just keeps on crawling the variations in an intelligent way, adding more analysis, and never stops until you tell it to.
  • Powerful interactive features allow you to influence the search.
  • Analysis can be focused on moves and variations that you consider important.
  • Overnight analysis produces hundreds or even thousands of analyzed positions.
  • IDeA stores the results in a chess tree on your hard disk.
  • Even if your computer crashes all your analysis will be there when you turn it on again.
  • Analysis can be stopped any time you like, and resumed later on.
  • IDeA uses the results of previous analysis, even if you start from a different position.
Read more about Interactive Deep Analysis with ChessOK Aquarium Basic.

Infinite analysis is enhanced with unique features, such as Infinite Analysis History. If you think you may have analyzed an interesting position two months ago, there is no need to guess. Just take a quick look at the Infinite Analysis History.
  • Analysis is stored in a chess tree which can be viewed in the tree window.
  • Multiple chess engines can be run simultaneously either in one window or in seperate windows.
  • Special threats analysis, multivariation mode, selected moves exlucsion, only tree moves analysis, etc.
Read more about Infinite Analysis with ChessOK Aquarium Basic.
ChessOK Aquarium Basic Screenshot
Game Analysis and Find Blunders. Automatically analyze your games. Read more.

CTG and Native Opening Books And Trees

ChessOK Aquarium Basic Screenshot ChessOK Aquarium Basic introduces state of the art chess trees which are fast, powerful and compact. It also reads and converts Chessbase/Fritz opening books (CTG). You would find useful to:
  • Switch quickly between opening books when analyzing
  • Create a tree configuration consisting of several opening trees.
  • Add the best variation from a tree to your game with the single click of a button.

Annotate Your Games… And Chess Trees!

ChessOK Aquarium Basic offers a broad range of opportunities on how to annotate games and chess trees:
  • Use Chess Informant style (symbols), record verbal commentary, apply board graphics etc.
  • Insert reference games from a database and endgame information from tablebases.
  • Annotate a move or a position just once and you will see your annotations everywhere the same position comes up.

Database compatibility: Chessbase and Chess Assistant

ChessOK Aquarium Basic reads and converts the most widely used database formats, including:
  • Chessbase (CBH)
  • Chess Assistant (CDP)
  • DSN (Aquarium)
  • PGN
  • EPD

Support for Most Chess Engines

ChessOK Aquarium Basic supports both UCI & WinBoard protocols, which are used by most modern chess engines. That means you can easily connect other UCI and Winboard engines to it, like Shredder, Junior, Naum, Zappa etc.

Play: Normal, Handicap, Chess960, Playing Zone Server

ChessOK Aquarium Basic allows you to play chess both vs computer (chess engine) and real players:
  • Three handicap modes, including predefined material and elo rating lists
  • Support for Chess960/Fischerandom games.
  • Blindfold and semi-blindfold games.
  • Free online play at the ChessOK Playing Zone.
  • Broadcasts of the most important chess events on the Playing Zone, with live Rybka analysis.
ChessOK Aquarium Basic Screenshot

Engine tournaments and matches

ChessOK Aquarium Basic Screenshot ChessOK Aquarium Basic is a powerful framework for organizing engine tournaments and matches:
  • Flexible definition of time-controls.
  • Opening book selection and maximum number of moves played from book.
  • Start from the standard starting position or any other position.
Rybka Randomizer matches can often give you the correct answer in your analysis where you suspect that the engine evaluates a positions incorrectly.

Rybka 2.2n2 – the Strongest Freeware Chess Engine

Rybka 2.2n2 – the Strongest Freeware Chess Engine. Aquarium’s advanced analysis functions take full advantage of Rybka’s strength. Rybka 2.2n2 is UCI engine, meaning that it can be extracted from Aquarium and connected to any chess program that supports UCI protocol, like Fritz (Chessbase) or Arena.

Try it in action

downloadDownload demo version

Documentation & Updates

Compare to other Aquarium Packages

Aquarium is available in four packages. All packages contain fully featured Aquarium interface. The differences are in chess engines, additional databases included and, of course, prices:
  ChessOK Aquarium Basic ChessOK Aquarium Standard Rybka 3 Aquarium Deep Rybka 3 Aquarium
Chess engine included Rybka 2.2n21 Rybka 2.3.2a2 Rybka 33 Deep (multi-processor) Rybka 33
Engine ELO rating4 3000 3066 3155 32175
Chess960 (Fischer) supported supported included included
Databases, games 6,000 3,700,000 3,700,000 3,700,000
Chess tree, positions 100,000 30,000,000 30,000,000 30,000,000
Price from €19.9 / $25 from €34 / $40 from €45 / $59 from €79 / $109
More detailed table
1 Rybka 2.2n2 is the strongest freeware engine. 2 Rybka 2.3.2a is the 2007 World Computer Chess champion. 3 Rybka 3 is the 2008 World Computer Chess champion. 4 As measured by CCRL40/40 rating list 5 On multi-core computer Aquarium can read data from different database formats and works with any modern chess engine, so it is possible to use the databases and engines you already have. Free databases also can be downloaded from the Internet. ChessOK Aquarium Basic and Standard are available for download only as of now, other packages can also be bought on DVD.


  • ChessOK Aquarium Basic – is recommended for those who don’t need the full power of the world’s strongest chess program, only the engine to play chess from time to time. It is also recommended for those who already own Rybka 3 and wants to try out the possibilities of the Aquarium chess interface.
  • ChessOK Aquarium Standard – is recommended for those users who already own the Rybka 3 engine, but also want up-to-date games databases and opening tree with engine evaluations. It’s a unique offer for the price specified, the alike packages from competitors cost as much as 3 times more.
  • Rybka 3 Aquarium is recommended for everyone seriously interested in chess, and have single-processor computer. This package is the most powerful computer chess analyst, in many aspects more powerful than the leading human Grandmasters.
  • Deep Rybka 3 Aquarium is recommended for the chess enthusiasts who need the highest quality analysis in a limited time. A powerful, multi-processor (multi-core) PC with Deep Rybka 3 Aquarium will become yur own chess analysis center, equal in analysis quality to the group of several grandmasters.
Packages can be bought either for download, or on DVD with printed manual. If you buy a version on DVD you can also download it before your DVD gets shipped.

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