The C4, or Commons + 4 Rares, format is used in our Hearthstone Midseason Open tournament.
- Decks are limited to basic and common cards only, plus 4 total rares. No epic or legendary cards are allowed.
- Rares are limited to 4 total cards per deck, not 4 unique cards, so 2 copies of 2 different rares would meet the limit.
- Cards of any rarity may be played if discovered through an in-game mechanic.
- Decks are also limited to standard cards.
- For regular play, we stick to regular Conquest (three decks is a lower bar for new players), though competitive play should consider adding a “Bring 4, Ban 1” provision to prevent the overwhelming power of Warlock Zoo from warping the meta in this format.
Goal: The C4 format helps level the playing field between players with large card pools and newer players, while allowing for a wider variety of deck archetypes. There is still an advantage to the more experienced players, but newer players have a better chance to stay closer, win occasional games, and be generally competitive.
(See also: Analysis of the Commons format)
Allowing 4 rares in a deck changes things slightly from the Commons format. Board and Card Advantage will still be relevant, but rares open up some increased synergy options, can potentially have a higher power level, and can enable decks to be built specifically around the card, as they tend to have more interactions than basics and commons. A C4 deck also has the potential for more payoff from themes than in a Commons deck.
Hunter: [Savannah Highmane] – adding Highmane to a B/C deck doesn’t fundamentally alter the way they play, but it will be a strict upgrade over whatever was previously in the deck. This the most basic improvement that adding rares will allow, but just because it’s basic doesn’t mean it’s not powerful or worthwhile. Highmane is GREAT.
Neutral: [Knife Juggler] – adding [Knife Juggler] to almost any low-curve deck that plays out a bunch of creatures is likely to generate a good bit of value when played right, and as such, it’s a very good 2-drop for that style of deck without changing the overall feel of the deck.
Mage: [Flamewaker]/[Demented Frostcaller] – these are good examples of build-around cards. They could slot into a pre-existing mage deck and help out a bit, but they’re at their best when you craft a deck around them with cheap spells that might not otherwise get played, but create value when played with one or both of these cards out.
Warrior (technically neutral): [Grim Patron] – Patron is a neutral card, but goes exceptionally well with warrior’s ability to deal a single damage to a lot of different things at once. It only requires an increased commitment to whirlwind type effects to really benefit it, rather than requiring you to build from scratch but is still a potentially strong build around.
Paladin: [Divine Favor] – as previously discussed, one of the issues with non-Warlock aggro is that they tend to run out of cards. [Divine Favor] potentially allows paladin to refill its hand after playing out a bunch of early guys, and really makes that style of deck potentially viable, rather than fringe playable.
Rogue: [Unearthed Raptor] – if a rogue deathrattle deck is viable, this card will likely be a major reason why. The ability to copy deathrattle effects on an efficient body is a really nice boost to a deathrattle based deck, which doesn’t really exists in basics/commons only.
These a just a few examples of the possibilities with a C4 deck. The rest are left as exercises for the reader.