Davy Back Fight

Davy Back Fight (デービーバックファイト) is a game between two pirate crews to win each other's crewmates to strengthen the crew. This event was first introduced in chapter 306 and episode 208.

History
All that is known is that one day, on a far away pirate island, somewhere, long ago, some pirates created a game to strengthen their crew.

Traditions
In order for the Davy Back Fight to begin, both captains must agree to the terms. If the terms are agreed upon, both captains will fire a gun at the same time into the air, sealing the agreement. Right after, the exact rules will be said to the crew of both teams. The three main rules are the basic traditions of the game.


 * Any crew members or symbols lost during the Davy Back Fight may only be retrieved during a Davy Back Fight.
 * Selected crew members must immediately swear loyalty to their opponent's captain.
 * If your symbol is taken, you must never raise it again.

Rules
If a crew wins a challenge, it is the captain's job to pick the team member they want. They have a right to know the person's profession on the ship. If the captain does not like anyone, they may take the crew's Jolly Roger, requiring the crew to remove their flags and sails, which may not be used again. The only exception may be if it is somehow won back. It is also assumed that if the winning crew wants, they may use any of the symbols they have stolen, but so far this does not seem to be the case.

The captain who initiated the challenge is allowed to pick which rule set to play by, 1, 2, or 3 coins is standard. Some captains allow their opponents to pick, but this is unusual, and mostly happens when the captain feels they will win no matter what, and it doesn't matter. That amount of coins is then tossed into the sea, to tell Davy Jones about the challenge.

Captains and teammates are allowed to interfere with anyone, this includes attacking enemies playing the game by any means.

Games Played
The games are the main event. Players for each game are chosen before-hand. If anyone playing round 2 is lost in round 1, the team with the missing member must play without that member. Once the teams are chosen, they cannot be changed later.

Donut Race
The Donut Race (ドーナツレース Dōnatsu Rēsu) is a race, where three team members from each crew are given materials (mostly barrels) and must build their own boat using them. Each team then uses their boat to go around the island (or part of the island they are on, if there is a smaller island right next to it, or part of the main one) and the first person to reach the finish line wins. Both team are allowed to use weapons, and can do anything, including pushing the other boat backwards, do damage to the other boat and even kill all the members of the opposing team. The other members of the crew can also support the team.

Groggy Ring
This game (グロッキーリング Gurokkī Ringu) is played normally with three players. One player is the "ball" on each team, and it is the goal of the opposing team to knock the player that is the "ball" into the opposing team's goal. The goal is a large, circular tube, used in a way similar to a basketball hoop. No weapons are allowed (though if the referee doesn't notice the weapons, they can be used).

Captain's Fight
The main event, the Captain's Fight is a duel between the two captains. A cannon is fired and wherever, or whatever it lands on becomes the ring. While inside the ring, the opponents are allowed to use any object or weapon in the arena. Devil Fruits are also allowed. The first person out of the ring loses. This includes being blown to bits and a shred of the person lands outside the arena, or the opponent throwing a piece out.

The Extra Games
In the anime, there were other games added when Luffy agreed to a second fight.

This game has five rounds. If one team gets three wins the game is automatically over. The goal in this game is to skate as many laps as one can before the time runs out. When the first ten seconds pass, there would be a signal to call the next group to skate. Players are not allowed to skate backwards or out of the ring or they will immediately lose the round, although the air is safe as long as they don't touch the ground.
 * Filler Game 1: Roller Skate

There has been no limit for participants. The two groups choose which members get to be the outsiders and which get to be the insiders. The game is like real dodgeball. In this game, one not allowed to hit another person's face, not allowed step out of the playing field and not allowed to break or eat the ball (this game appears to be prepared for all contingencies). Cheating in this game is against the rules and cheaters are decapitated. No weapons are allowed except for a contraption called Dead Hit-Kun (a giant ball launcher).
 * Filler Game 2: Hit and Dead Ball

It is just like the real game but in this one, weapons and attacking are allowed.
 * Filler Game 3: Red and Green Light

None of these extra games are official, but since the Davy Back Fight probably has many games, there is nothing making them unofficial aside from the fact that they were filler made by Toei Animation and not shown in the manga.

Davy Back Fight Filler

 * In the manga, a person is only allowed to enter one game (e.g.: If Robin enters the Donut Race, she is not allowed to enter the others).
 * In the anime, a person is allowed to enter two games.
 * In the manga, Nami, Robin, and Usopp were the only members of the Straw Hat crew who entered the Donut Race.
 * In the anime, all the Straw Hat crew members enter the Donut Race.
 * In the manga, the third match was the captain's Fight.
 * In the anime, the third match was changed to Roller Skate instead to extend the arc, as Chopper was won back in this round.
 * In the manga, Chopper was supposed to participate in the Groggy Ring battle but couldn't because Foxy chose Chopper to be in his crew, so Chopper in the manga never has the chance to participate in any of the Davy Back Fight games.
 * In the anime, the Davy Back Fight arc was extended because Chopper was won back at the end of the first match, so Chopper was able to participate in the Dodgeball and Red and Green Light games.
 * In the manga, when Luffy woke up after beating Foxy, he was first given an option to pick anyone from Foxy's crew to be in his crew. But Luffy refused, (making Sanji upset that Luffy didn't chose Gina). He chose Foxy's flag and redesigned it. After that, Foxy and the rest of his crew departed, mad at Luffy's decision.
 * In the manga, after winning the Groggy Ring, Luffy chose Chopper back in his crew.
 * In the anime, Luffy chose Shelly instead of Chopper. Luffy then lost the other rounds and chose back Tonjit while losing Robin. Luffy never got Chopper and Robin back until after he defeated Foxy.
 * Before the Davy Back Fight game starts, the captain of each crew must choose which game their crewmates participate in, but when the Straw Hats were playing in the Davy Back Fight for the second time, after they lost the dodgeball game, Luffy stated that he wants to play the next game even thought he is not allowed to (anime only).

Trivia

 * For rule #3, the exception may be if one wins it back, as in rule #1. This was never stated, but the wording implies it to not be true. However, the rules also state that won members are immediately part of the crew and cannot quit and return.
 * Foxy the Silver Fox had a total of nine hundred twenty wins, and one loss, that loss being against Luffy.
 * Since Foxy only has five hundred crewmates, the numbers don't add up. He never had a loss before Luffy, so that means nine hundred twenty games, with 1, 2 or 3 coin rules, meaning he had an opportunity to gain more than three times the number of crewmates. Taking into account some people played more than once, and the ability to take flags, he should have plenty more. However it could be that many of his previous crew members died in battle considering the low strength of his crew, or could have simply left the crew for other reasons. Also, for some of the matches he may have taken his opponents' flags.