Question: Which board game features a rule for performing captures, making it unique among connection games, Stratego or Onyx?
Context: Stratego is a strategy board game for two players on a board of 10×10 squares.  Each player controls 40 pieces representing individual officer ranks in an army.  The pieces have Napoleonic insignia.  The objective of the game is to find and capture the opponent's "Flag", or to capture so many enemy pieces that the opponent cannot make any further moves.  "Stratego" has simple enough rules for young children to play, but a depth of strategy that is also appealing to adults.  The game is a slightly modified copy of an early 20th century French game named "L'Attaque".  It has been in production in Europe since World War II and the United States since 1961.  There are now 2- and 4-handed versions, versions with 10, 30 or 40 pieces per player, and boards with smaller sizes (number of spaces).  There are also variant pieces and different rulesets. Luzhanqi () (lit.  “Land Battle Chess”) is a two-player Chinese board game .  There is also a version for four players.  It bears many similarities to Dou Shou Qi, Game of the Generals and the Western board game Stratego.  It is a non-perfect abstract strategy game of partial information, since each player has only limited knowledge concerning the disposition of the opposing pieces.  Because of the Chinese nature of the game, terms used within the game may vary in translation. Buga-shadara, also known as Bouge Shodre, is a two-player abstract strategy board game from Tuva, a republic in Siberia, Russia.  It is a hunt game where one player plays the deers (which is "buga" in the Tuva language).  There are two deers usually represented as the black pieces.  The boars are also referred black in the referenced article "Buga-shadara a folk game from Tuva".  The other player has 24 white pieces with dogs associated to them.  The board consist of an Alquerque board flanked on two of its opposite sides by a square patterned board (referred to as "side-houses" in the referenced article).  Because the board is in part an Alquerque board, this makes Buga-shadara a tiger hunt game (or tiger game).  What makes Buga-shadara unique among tiger games are the expansion boards on the two opposite sides of the Alquerque board.  They are square, whereas most are triangle-like.  The word "shadara" resembles the word "shahdara".  The "shah" part "is a title given to the emperors/kings and lords of Iran (historically also known as Persia)." .  There is a place called Shahdara Bagh in Lahore, Punjab, Pakistan, and it's thought that the word "Shahdara can be translated as "the way of kings".  Shah translates as "king" and dara translates as the way of kings."  The referenced article associates the boars (the two black pieces) as kings.  Perhaps the boars or deers are kings, and have to find a way or have a way with the white pieces or dogs. This is a list of games on the Wii video game console that use WiiConnect24.  WiiConnect24 games are distinguished from Wii Wi-Fi Connection games in that WiiConnect24 support only allows for passive connection between players, such as the sharing of credits in "" or "Metroid Prime Trilogy".  Some games support both active connectivity with the Nintendo Wi-Fi Connection (requiring an independent 12-digit Friend Code), as well as passive connectivity with WiiConnect24 (only needing the Wii's own 16-digit Friend Code), such as "Mario Kart Wii". Havannah is a two-player abstract strategy board game invented by Christian Freeling.  It belongs to the family of games commonly called connection games; its relatives include Hex and TwixT.  Havannah has "a sophisticated and varied strategy" and is best played on a base-10 hexagonal board, ten hex cells to a side. Onyx is a two-player abstract strategy board game invented by Larry Back in 1995.  The game features a rule for performing captures, making Onyx unique among connection games. Selfo is a class of abstract strategy board games subscribed to the category of connection games. Its name derives from the phenomenon of self-organization (increase in a system's organization without external guidance), since during the game the sets of pieces might flow in a coordinated way as they step on the board.  Despite its very simple definition (“group your set of pieces by moving in turns to adjacent cells”) complex self-organization processes take place during the game under concrete circumstances (a balanced distribution of pieces and players with a similar level of expertise), and is the result of abrupt and deep changes in the tactics.  The particular values given to the traditional parameters that define a game (i.e., board tiling, size and initial position, or number of pieces and players) are not so relevant, and many variants have been found to meet the conditions for self-organization.  The "Selfo" class of connection games is defined, instead, by the interrelations among parameters in order to favor self-organization.  Subclasses of Selfo derive upon the move length (number of movements of a piece in a single turn to adjacent empty cells).  In a generic "Selfo"-"n" game, a player can move one piece from 0 (passing on the turn) to "n" consecutive steps. A connection game is a type of abstract strategy game in which players attempt to complete a specific type of connection with their pieces.  This could involve forming a path between two or more goals, completing a closed loop, or connecting all of one's pieces so they are adjacent to each other.  Connection games typically have simple rules, but complex strategies.  They have minimal components and may be played as board games, computer games, or even paper and pencil games. TAMSK is the second board game in the "GIPF" Project of six abstract strategy games, and was published in 1998.  Players move sand hourglass timers and drop plastic rings around spaces on a hexagonal board in an attempt to limit their opponent's moves.  Each player starts the game with 32 rings, and the player with the fewest remaining rings at the end of the game is the winner.  The game is unique among the "GIPF" Project games in having time as a central game component, and the manner in which time is used is possibly unique among board games in general. Stratego: Legends is a strategy board game created and released by Avalon Hill in 1999, with rules similar to "Stratego".  Set in a mythical world called "The Shattered Lands", it pits the forces of good (represented by beige-back pieces) against the forces of evil (represented by gray-back pieces).  It plays similar to the original "Stratego" game, and also somewhat similar to chess.  The game was discontinued by Avalon Hill in 2004.
Answer: Onyx