The Coin

The Coin is a special uncollectible spell card granted at the start of each game to whichever player is selected to go second. Together with the fourth starting card, The Coin is intended to counter some of the disadvantage of going second, although going first is still slightly better on average.

How to get
The Coin is generated once at the start of each game, for the player selected to go second. It is uncollectible and cannot be included in players' decks.

Generated by
This card can also be generated by the following cards.

Against bosses
The following cards will generate The Coin when played against an adventure or Tavern Brawl boss, or the playable Ragnaros the Firelord hero.

Strategy
The Coin can be used at any time during the game to give the player an extra Mana Crystal. It is possible for The Coin to be used more than once each game with the use of copying effects like Lorewalker Cho or Mind Vision, or with cards that generate new The Coin cards like Cutpurse.

This can be useful in the early or late game to play a card one turn earlier than they would otherwise be played. In the early game, it can help to overcome a difficult card draw, or to allow you to place a high-cost minion on the field ahead of time. In the later game, it can be saved until an opportunity presents itself for The Coin's extra mana crystal to provide a substantial benefit.

The Coin is a regular card, and counts towards your hand size, so you may want to keep it in your hand to use it with cards that counts towards your hand size, such as Twilight Drake. It also counts as playing a spell, which is significant for cards such as Mana Wyrm and Archmage Antonidas.

Players have a maximum of 10 mana. If you play The Coin with 10/10 mana, the extra mana will be wasted. Instead, one should play any card that uses mana and then play The Coin to refill an empty mana crystal.

Cosmetic Coins
Starting from Patch 19.0, the player can customize The Coin's art with a set of alternative cosmetic Coins. As such, cosmetic Coins purely do not affect gameplay in any way. Below is the list of available cosmetic Coins the player can unlock and use.

Functionality
Similar to alternate heroes:
 * Cosmetic Coins are permanent additions to the game; once purchased or earned. Some Coins are available for purchase or reward only through time-limited promotions, but once a Coin is unlocked, it can be used at any time.
 * Cosmetic Coins can be used in any game mode.
 * Once purchased, players can select cosmetic Coins through the Collection manager. Players can choose a default "favorite Coin". Favorite Coin will be given to the player whenever they go second.
 * Cosmetic Coins have their own art, golden art animation, and SFX animation when played.

Design
The Coin was designed to counter the disadvantage of going second in a match. A variety of approaches were considered and tested for this purpose, including Avatar of the Coin, and the second player starting with 35 Health. However, The Coin (as well as drawing an extra card) was ultimately selected to even the balance.

In March 2015 Brode stated, "the win rate is very close to 50-50 regardless of who has the coin", but that "Going 1st is slightly better". With regard to tournaments and high level play, Brode confirmed that even in the "very top 0.01%" it's "still better to go first, on average". This state of affairs was confirmed in April 2016.

Previously, during the late beta on 5th February 2014, Ben Brode stated "It's about three percent better to go first over second. It's only a tiny bit better to go first at the lower levels of play." Eric Dodds followed this by asking "are there some decks which are built around going second, and might have a small advantage for going second? Yeah, that's certainly the case, but the advantage for going second in those decks I would imagine is less than one percent." Blizzard statistics from 8th November 2013 had previously shown a 51.3% win rate for high-ranked players going first, with a slightly higher 53% for players at lower levels.

It can be argued that good use of The Coin requires an additional degree of strategy, therefore offering a disadvantage for less experienced players.

Trivia

 * Gallywix's Coin (generated by Trade Prince Gallywix, a rogue legendary card from Goblins vs Gnomes), Counterfeit Coin (a rogue rare card from Mean Streets of Gadgetzan) and Innervate (a druid card from the Basic set) have the same effect as The Coin and — in the case of the former two — similar art.
 * The Coin often appears as currency in Hearthstone lore. Money-related effects are commonly shown as gaining 1 Mana Crystal. Cards like Cutpurse and Hoarding Dragon use the Coin as shorthands for money or treasure. Coins can also be seen throughout the Mean Streets of Gadgetzan trailer, taking the place of actual money.

Patch changes

 * Moved to Core set (from Basic).
 * Cosmetic Coins introduced. Flavor text added.
 * If a player’s deck contains all Golden cards, a Golden Coin will complement your deck if you happen to go second.