The matchmaker is one of the core mechanics systems of World of Warships.
It's a system that allocates players into teams.
Learning about the principles of matchmaking will help you determine
which ships your opponents and allies might have in battle,
and understand the factors upon which the waiting time in the queue depends.
Each ship in our game has an important parameter—
the battle tiers in which it can participate.
Usually, it's the ship's tier +2.
Detailed information about each ship
can be found in the World of Warships Wiki.
Let's see how two teams get assembled for a Random Battle.
First let’s select Tier VIII German cruiser Admiral Hipper
and click "Battle!"
The matchmaker starts its work.
Imagine each battle tier as being a big virtual basket.
The queue for Random Battles has eight baskets
for multi-tier battles from Tier III to X,
and ten baskets for single-tier battles.
Admiral Hipper is placed in four baskets simultaneously—Tiers VIII to X—
and additionally, a basket in which only same-tier ships are put together.
In our case—Tier VIII ships.
The battle tier is defined by the ships with the highest tier in the battle.
For example, in a Tier IX battle,
Tier IX is the highest tier, and, as you've probably guessed,
you can encounter Tier VII and VIII ships in those battles as well.
One of the primary tasks of the matchmaker is to assemble teams
that are as symmetrical as possible,
so that no team has any advantages because of their roster.
That's why the teams are assembled according to a set of quite strict rules.
The matchmaker initially tries to find the exact mirror match
for the German ship— another Tier VIII cruiser.
While looking for it,
the system doesn't consider a ship's modules,
mounted upgrades, consumables, or Commander skills.
Only her type and tier matter.
There are some exceptions that we'll discuss later,
but this rule is scrupulously followed for the ships that define the battle tier.
This is why the matchmaker will never match Admiral Hipper
with a Tier VII cruiser or battleship in the Tier VIII basket.
After our German ship, Tier VII battleship Colorado appears in the queue.
It gets placed in three baskets for multi-tier battles—Tier VII, VIII, and IX.
The matchmaker starts looking for a match for it too,
among the ships that are already in these baskets.
If it can't find any, it searches among any newcomers.
Gradually, the baskets get filled up with ship pairs
according to their battle tier.
There are restrictions on the number of ships
of one tier within each multi-tier basket.
Firstly, no more than five pairs of ships of the same tier as the battle tier.
This means that, apart from our Admiral Hipper and its opponent,
the Tier VIII basket can have no more than four pairs of "eights."
Secondly, Tier VII to X battles must have at least three ship pairs
that are two tiers lower than the battle tier.
That's why the same Tier VIII basket will have at least three pairs of "sixes."
This requirement allows the ships at the bottom of the roster
to feel more comfortable in a battle
and gives them a chance to have a greater impact on its outcome.
Finally, there are restrictions on ship types.
No more than five battleships, four destroyers, and one aircraft carrier.
Those ship types whose slots in baskets are occupied
will wait until the assembled team enters battle,
and only after that will they take their places in the empty baskets.
Let's get back to our Admiral Hipper.
The Tier VIII basket lacks one pair to send the ships to battle;
the Tier IX basket lacks three pairs;
and the Tier X basket doesn't have any "tens,"
and without them the battle won't start,
even if the queue for Tier X consisted of 12 pairs.
Our old acquaintance—Fuso— appears in the queue,
followed by another "six"—New Mexico.
The matchmaker makes a pair of the two battleships.
As we can see, the Tier VIII basket is the first to assemble
two full teams with 12 ships in each.
The matchmaker now performs the final balancing.
At the moment, we have four Soviet destroyers in one team
and four Japanese destroyers in another.
The matchmaker will distribute them evenly.
If three out of four destroyers of the same nation were in a Division,
only the ship without a Division would be moved.
You probably know that the battle tier of a Division is determined
by the highest tier of a ship in a Division.
At the same time, the matchmaker will first try to find a similar Division
for the opposing team or the same individual ships.
For example, if you and your friend enter a battle
playing cruiser Hipper and destroyer Kagero,
it's possible that the opposing team will have a Division comprising
cruiser Mogami and destroyer Benson.
At the same time, a team can have only one Division more than the other team.
The difference in ship tiers within a Division can't be more than one.
So, no matter how hard you want it,
you won't be able to invite Fuso to a Division with Admiral Hipper.
The teams are now assembled.
All the ships in these teams are removed from all the other baskets,
and the last thing that the matchmaker does is select a random map
that’s suitable for a Tier VIII battle.
Usually, the matchmaker needs very little time
to assemble teams for Random Battles.
Often, you see the battle loading screen several seconds after you click
the "Battle!" button.
However, it can happen sometimes that the tier baskets available to you
don't have enough ships.
In such cases, the time required to assemble teams can be longer.
After the first player in the queue has been waiting for more than 3 minutes,
the matchmaker applies a new, softer, settings template.
First, each team is now allowed to have up to seven ships
of the same tier as the battle tier.
Second, the ship type restrictions become a little softer.
For example, six battleships are allowed per team.
Finally, the matchmaker lowers the requirements
for mirroring ship types in the teams,
except for those ships that define the battle tier.
For our Hipper, just as for any other Tier VIII ship in the Tier VIII basket,
the mirroring requirement when looking for its pair remains the same.
However, in the same basket,
a Tier VII destroyer can be matched with a Tier VI
or Tier VII cruiser, for example.
That's why a situation is possible where teams can have
an uneven number of ships of one type.
A team can have one destroyer, one battleship,
and two cruisers more than the other team.
There are no exceptions for aircraft carriers though,
regardless of their waiting time.
The only thing that the settings allow is
two aircraft carriers per team after a long wait.
Apart from that, in Update 0.8.7,
we introduced an important feature— calibration of battles for each ship tier.
It means that, if you fight 20 battles playing a Tier VIII ship, for example,
you'll encounter Tier X ships no more than eight times.
This is because a rule is now in place
that restricts Tier VIII ships from being placed in battles with "tens"
in more than 40% of cases.
Each time you enter the queue,
the matchmaker analyzes your last 20 battles at the ship tier you selected,
regardless of its type.
Please note that the system keeps separate records for Co-op and Random Battles.
Now, let's review two rare cases of matchmaking
that cause a lot of questions from players.
The first happens when the matchmaker assembles two mirrored teams
with five ships each in the Tier X basket.
There are no more suitable ships in the Tier VIII, IX, or X baskets,
and the first player has already been waiting in the queue
for more than 5 minutes.
In this case, the matchmaker can send two incomplete teams into battle.
In Co-op Battles, the matchmaker works in the same way.
For the AI-controlled team, it picks ships of the same type and tier
that players took into battle.
In Ranked Battles, baskets in a battle queue
are distinguished depending on the League.
For example, the matchmaker will only place players
from one league in a team with the same-league players.
The waiting time of the first player in the queue is not limited,
and there will be no relaxing of the matchmaker’s settings,
apart from an increased number of same-type ships.
We hope that we’ve managed to effectively explain how the matchmaker works,
but if you still have questions about team rosters—
let us know in the comments!
Until next time!