# Reconnaissance Blind Chess > Chess variant with imperfect information and private sensing mechanics. (iPhone/iPad app by Johns Hopkins University Applied Physics Laboratory.) - Source: https://appshunter.io/ios/app/reconnaissance-blind-chess/id1631199541 (this page in markdown: same URL + `.md`) - Developer: [Johns Hopkins University Applied Physics Laboratory](https://appshunter.io/developer/473217885) - Category: Education - Price: Free - Rating: 5.00/5 from 4 App Store ratings - Age rating: 4+ - Requires: iOS 14.0 · 22 MB - Languages: English - Released: 2022-08-23 - Data updated: 2026-06-07 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/reconnaissance-blind-chess/id1631199541/reviews.md ## What is Reconnaissance Blind Chess? The Reconnaissance Blind Chess (RBC) variant was invented in 2015 at JHU/APL as an experimentation platform to study artificial intelligence (AI). RBC includes imperfect information, long-term strategy, explicit observations, and very little common knowledge between opponents. In the RBC variant, the opponents cannot see each other’s pieces but can learn about them through private, explicit sensing actions. In unranked RBC games, the player plays with a guest account. They choose their opponent from a list of available bots and select their color (white or black). An unranked RBC game will not affect the player's rating. In ranked RBC games, the player logs in with their RBC account credentials, and their opponent and color are chosen at random. It may take a few seconds to be matched up against an opponent. A ranked RBC game will affect the player's rating. Game Rules: Reconnaissance Blind Chess (RBC) was intentionally designed to keep the game as close to traditional chess as possible while adding an appropriate amount of uncertainty and explicit sensing. RBC is like chess but includes the following core differences: A player cannot see their opponent's pieces. Prior to making each move, a player selects a 3×3 region of the chess board (via green outline on the relevant squares) to “sense” the pieces in that region. The player is informed of the true piece configuration within the sensed 3×3 region. The opponent is not informed about where the player sensed. When a player captures a piece, they are informed (via red outline on the relevant square) that they made a capture, but they are not informed about what piece they captured. When a player's piece is captured, they are informed (via red outline on the relevant square) that their piece was captured, but they are not informed about what piece captured it. There is no notion of check or mate because neither player can be definitively aware of any check relationship. A player wins by capturing the opponent's king or when the opponent runs out of time. Each player begins with a cumulative 15-minute clock to make all their moves. If a player tries to move a sliding piece through an opponent's piece, the opponent's piece is captured and the moved piece is stopped where the capture occurred. The moving player is notified of the square where the piece landed (via red outline on the relevant square), and both players are notified of the capture in the manner stated above. If a player attempts to make an illegal move, such as a pawn diagonally to an empty square, or a pawn forward to an occupied square, or a castle through an interposing piece, they are notified that the move did not succeed and their turn is over. However, castling through check is allowed because the notion of check is removed. There is a "pass" option that a player can select if they prefer to make no move during their turn. A player has access to reserve pieces that they can drag on and off the board to better visualize the state of the board, based on their belief of where their opponent's pieces are located. The turn tracker informs the player when it is their turn to sense and move, and when it is the opponent's turn. ## Key features - Imperfect information gameplay - Private sensing actions - Ranked and unranked game modes - AI bot opponents - Capture-based win condition - Time-based win condition ## Frequently asked questions about Reconnaissance Blind Chess ### What is Reconnaissance Blind Chess? Reconnaissance Blind Chess (RBC) is a chess variant invented at JHU/APL. It introduces imperfect information, where players cannot see each other's pieces, and requires strategic use of sensing actions to gather information. ### How does sensing work in Reconnaissance Blind Chess? Before each move, players can select a 3x3 region of the board to sense. They are then informed of the exact piece configuration within that sensed area, but the opponent is not notified of the sensing action. ### How do you win in Reconnaissance Blind Chess? A player wins by capturing the opponent's king or when the opponent runs out of their allocated 15-minute clock time. There is no traditional check or mate due to the imperfect information. ### Can I play Reconnaissance Blind Chess offline? The provided information does not specify offline play capabilities. However, playing against AI bots suggests that some form of local play might be possible. ### What devices does Reconnaissance Blind Chess support? Reconnaissance Blind Chess is available on iPhone, iPad, and iPod devices, indicating compatibility with iOS platforms. ### What is the age rating for Reconnaissance Blind Chess? The app has an age rating of 4+, making it suitable for a wide range of players interested in strategic board games. ### How often is Reconnaissance Blind Chess updated? The app was last updated on April 23, 2025, indicating recent development and support from the developer. ### What is the user sentiment for Reconnaissance Blind Chess? Based on the provided data, the app has a perfect 5.0-star rating from 4 ratings, suggesting very positive user sentiment among its current players. ## Version history (last 2 releases) ### 1.1.1 — 2025-04-23 - Added human versus human gameplay, - Added landscape mode for iOS - Fixed font sizes in certain screens - Made button clicks more visible ### 1.0 — 2022-08-24 No release notes. ## Apps similar to Reconnaissance Blind Chess | App | Rating | Price | Category | | --- | --- | --- | --- | | [LearnEU EuroQuiz](https://appshunter.io/ios/app/learneu-euroquiz/id6444339972) | — | Free | Education | | [BookMoves](https://appshunter.io/ios/app/bookmoves/id6469711333) | 4.5 (4) | Free | Education | | [GCB Link](https://appshunter.io/ios/app/gcb-link/id1589616246) | 4.8 (6) | Free | Education | | [Epictale: Dreamy Sensory Tales](https://appshunter.io/ios/app/epictale-dreamy-sensory-tales/id6477192402) | 5.0 (2) | Free | Education | | [International Chess Academy](https://appshunter.io/ios/app/international-chess-academy/id6470895163) | — | Free | Education | | [DigiChess](https://appshunter.io/ios/app/digichess/id1642997321) | — | $5.99 | Education | ## More apps by Johns Hopkins University Applied Physics Laboratory - [New Horizons: a NASA Voyage to Pluto](https://appshunter.io/ios/app/new-horizons-a-nasa-voyage-to-pluto/id473217882) - [CassiniMIMI](https://appshunter.io/ios/app/cassinimimi/id1153077273) - [Van Allen Probes Science](https://appshunter.io/ios/app/van-allen-probes-science/id1463639579) All apps by Johns Hopkins University Applied Physics Laboratory: https://appshunter.io/developer/473217885 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-07.*