Trainer Battle (GO)

Trainer Battles (Japanese: トレーナーバトル Trainer Battle) are a feature in that allow players to challenge other players to a 3-on-3 battle. This feature was first introduced on December 12, 2018, and received a major update on July 19, 2019. On January 28, 2020, the GO Battle League was launched to introduce competitive, online Trainer Battles.
==Battle Challenge==
Players can challenge any player in close proximity by scanning another player's Battle Code from the Battle screen. These Battle Codes are different to the QR codes used to add , with a new one being generated every time the player signs into the game.
Players can also remotely challenge Ultra Friends and Best Friends by sending a Battle Challenge through the List. The Battle Challenge feature can be disabled via the settings page. Battling also counts as a daily activity that may increase Friendship level.
==Leagues==
Each player selects three Pokémon to battle with. Pokémon will automatically be recommended based on their in relation to a League's CP limit. Preset teams can also be made for each League from the Party screen. and cannot be used in Trainer Battles, although they can fight Team GO Rocket.
Players can choose to battle from three different Leagues:
League 	Max CP per Pokémon	Unlock requirements
Great League 	1,500 	None
Ultra League 	2,500 	3 Pokémon with CP 1,500+
Master League	No limit 	3 Pokémon with CP 2,500+
In addition to the above, in GO Battle League, the Little Cup, or a variant of it, may be available to challenge, with a CP limit of only 500.
==Battle mechanics==
:For a list of move data in Trainer Battles, see list of moves in Pokémon GO.
Similar to battling a , the player can command a Fast Attack by simply tapping the screen, which also charges up energy for the Charged Attack meter. However, there are several ways Trainer Battles differ from Gym and s:
* Moves often have separate power and energy boosts or costs
* All Fast Attack durations are measured in 0.5-second "turns"; Charged Attacks have no duration
* All attacks have a 30% damage boost
* No weather bonuses
* No dodging
* Receiving damage does not generate energy
* When a Pokémon faints, the player has 12 seconds to choose a Pokémon before the next Pokémon in the sequence is automatically sent out.
* Switching out Pokémon mid-battle has a 60-second cooldown period. Switching Pokémon also resets all stat changes.
** This countdown does not stop during Charged Attacks or when the opponent is selecting a Pokémon to send out
The battle has a four-minute timer and the last 20-second countdown is displayed. If the timer runs out, the player who has the most Pokémon remaining is declared the winner. If both players have the same number of Pokémon remaining, the player who has less damage to their remaining Pokémon wins the battle. Time spent charging up a Charged Attack is not counted against the timer. 
Pokémon used in Trainer Battles will always start off with full HP and, after battle, are reset to the HP they had previously; however, fainted Pokémon cannot participate.
Battles against Team GO Rocket members use the same Trainer Battle format. However, the player's Pokémon are not fully restored at the beginning, and medicine is required to restore any HP lost during the battle.
===Activating Charged Attacks===
Once the Charged Attack meter is full, the player can tap the icon to cast a Charged Attack. Activating a Charged Attack will initiate a five-second minigame in which type icons start appearing on the screen in a pattern specific to the Charged Attack's type. The more icons the player manages to swipe, the more damage the Charged Attack will deal. Since February 15, 2019, certain Charged Attacks may increase the user's s after use; on March 19, 2019, Charged Attacks that may decrease the target's stats were also introduced.
A damage multiplier is applied to the Charged Attack depending on how many icons the player successfully manages to swipe.
Score 	Min. Accuracy	Multiplier range
Base 	0% 	[0.25, 0.5)
Nice! 	30% 	[0.5, 0.75)
Great! 	 	[0.75, 1)
Excellent!	95% 	1
If both players attempt to cast a Charged Attack on the same turn, then the Pokémon with the higher Attack stat will go first. If there is a tie, then priority is given randomly.
===Protect Shield===
At the same time when a Pokémon is using a Charged Attack, the opponent also has the option to use a Protect Shield to mitigate all incoming damage. Each player can use up to two Protect Shields per battle. Using a Protect Shield will not prevent stat changes, to either the user or target, from an opposing Charged Attack.
The Protect Shield's size depends on the Pokémon's size, e.g. a 's Protect Shield will be smaller than an 's Protect Shield.
When a Protect Shield blocks a Charged Attack, it changes color based on the effectiveness of the blocked move. A super effective move causes the shield to turn red, a not very effective move causes the shield to turn blue, and a move of regular effectiveness does not cause a color change.GO Battle Day stream Feb 10, 2024
===Priority===
The execution time of Fast Attacks in Trainer Battles is measured in 0.5-second turns. The Fast Attack's damage is applied at the end its final turn. If the Fast Attack's user is knocked out before the move's final turn, then damage will not be dealt.
Given two opposing Pokémon in a Trainer Battle...
* If both Pokémon have cast a Fast Attack that complete on the same turn, then damage will be applied to both simultaneously. This can result in a double-knockout or a draw.
* If both Pokémon cast a Charged Attack on the same turn, the one with a higher Attack stat will go first; if the Attack stats are identical, then priority is randomly assigned. The other Pokémon will move immediately after, unless it was knocked out.
* If one Pokémon casts a Charged Attack and the other a Fast Attack, the Charged Attack will execute first. If the Fast Attack's user was not knocked out, its damage will be applied immediately after, regardless of its remaining turns. (This is unofficially called a "free turn" for the Fast Attack's user.)
** In Team GO Rocket battles, a Charged Attack will instead cancel the Fast Attack.
==NPC battles==
Some non-playable characters can be battled in Trainer Battles, such as in Battle Training, members Team GO Rocket, and s during certain in-game events. 
NPCs may use Pokémon with stats and CP that are unattainable by powering up. But they also battle in a very predictable manner:
* Pokémon are always sent out in the same order, and they are never switched out until they faint.
* Pokémon moves are randomly selected from their standard move pools, and they will only have one Charged Attack. They will never use moves that are event-exclusive or require an Elite TM to learn.
* "Easy" NPCs never use Protect Shields. 
** These include Great League and Ultra League Battle Training, s, and s.
* "Hard" NPCs always use Protect Shields against the player's first two Charged Attacks. 
** These include Master League Battle Training, s, and .
* NPCs will briefly pause and not use any attacks (est. 3 seconds or 6 turns) if either side
** Uses a Charged Attack, regardless if blocked by a Protect Shield.
** Switches in a Pokémon, except for sending out the initial one. This also includes switching in a Pokémon due to the previous one fainting.
NPC battles also handle move priority differently. This makes some advantageous scenarios in player-vs-player battles (PvP) become disadvantageous in NPC battles, or vice versa.
* If one side uses a Charged Attack while the opponent is in the middle of a Fast Attack, the Fast Attack is cancelled. 
** In PvP, the Fast Attack's damage and energy gain is applied immediately after the Charged Attack completes (i.e. a "free turn" for the Fast Attack user).
* If both sides simultaneously use a Charged Attack, only the side that has priority will execute it. 
** In PvP, the side without priority is locked into executing the Charged Attack immediately afterwards.
===Battle Training===
Battle Training is a type of Trainer Battle where the player battles one of the leaders, Blanche, , or Candela. It can be accessed from the "Training" section at the bottom of the Battle view.
Team leaders use Pokémon that have the maximum 15 s across all stats and are powered up to the highest integer level that meets the league's CP limit. In the Master League, the team leaders' Pokémon are powered up to Lv. 55, which is unattainable by players.
In Great and Ultra Leagues, team leaders will never use their Protect Shields. In Master League, they will always use a Protect Shield against the player's first two Charged Attacks.
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Team Mystic Leader			
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Team Instinct Leader			
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Team Valor Leader			
====Prior to July 19, 2019====
Prior to July 19, 2019, team leaders would never use Protect Shields, even in Master League. Their Pokémon, as listed below, were powered up as much as the league's CP limit allows.
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Team Mystic Leader			
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Team Instinct Leader			
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Team Valor Leader			
==Rewards==
After a battle, both players will receive a randomly-selected reward bundle. Each day, players can only receive rewards from Trainer Battles three times and training against a team leader once. There is also a 10% chance to receive a second reward bundle, regardless of outcome. Losing against a team leader always yields 300 instead of a random reward, but outcome does not affect the reward from battles against other players.
Rates for training against team leaders have been approximated based on empirical data.PvP Rewards: Drop Rates Demystified — The Silph Road
Potential rewards	Potential rewards	Quantity	Probability 	Probability 	Probability 	Probability
Potential rewards	Potential rewards	Quantity	Great LeagueTraining	Ultra LeagueTraining	Master LeagueTraining	PvP
 	 	××× 	93% 	90% 	83% 	67%
 	Sinnoh Stone 	×1 	5% 	6% 	10% 	15%
 	Rare Candy 	×1 	1% 	3% 	5% 	15%
 	Fast TM 	×1 	0.5% 	0.5% 	1% 	1%
 	Charged TM 	×1 	0.5% 	0.5% 	1% 	2%
==Medals==
Medals can be earned for winning Trainer Battles against other players in each league and for defeating a team leader. Each of these medals unlocks items that the player can then purchase using PokéCoins.
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Medal 	Task 	Bronze	Silver	Gold 	Rewards 	Rewards
Medal 	Task 	Bronze	Silver	Gold 	Male 	Female
 	Train ___ times. 	10 	100 	1,000	Ace PantsAce BootsAce Vest 	Ace BeltAce SkirtAce BootsAce Vest
Great League 	Win ___ Trainer Battles in the Great League. 	5 	50 	200 	Ace GlovesAce EarbudVeteran Pants	Ace GlovesAce VisorVeteran Leggings
Ultra League 	Win ___ Trainer Battles in the Ultra League. 	5 	50 	200 	Ace TopVeteran Jacket 	Ace Long TopVeteran Coat
Master League	Win ___ Trainer Battles in the Master League.	5 	50 	200 	Ace ShortsAce ShoesVeteran Boots 	Ace ShoesVeteran Boots
==Updates==
* Prior to July 19, 2019, a player using a Charged Attack would instead repeatedly tap the screen for three seconds to strengthen its power. If the player did not tap the screen at all, the Charged Attack would only deal 1 HP damage.
* Prior to December 11, 2019, if both players attempt to cast a Charged Attack at the same time, priority is given to whomever selects their team first
==References==
Category:Pokémon GO
Category:Terminology
Category:Game mechanics
de:Trainerkampf (Pokémon GO)
es:Combate de entrenador (Pokémon GO)
ja:トレーナーバトル (GO)