Splat Zones

Splat Zones is one of the three Ranked Battle modes in Splatoon and Splatoon 2, alongside Tower Control and Rainmaker. Splat Zones was the first Ranked Battle mode introduced in the series.

Splatoon
Splat Zones was announced on March 23, 2015 when video game journalists from around the world were invited to a Nintendo event in Seattle, Washington. It was revealed that this mode would not be available at launch, but would instead be released at a later, unspecified, date. Splat Zones, along with the Ranked Battle section of the lobby, was added to the game on June 1st 2015 after enough players reached Level 10.

Splatoon 2
Splat Zones was first confirmed to return for Splatoon 2 on June 2, 2017 in a Nintendo YouTube video.

Description
Splat Zones plays similarly to the King of the Hill mode in other video games. It revolves around a number of "zones", usually one single zone in the center of a map, which players must attempt to cover in ink. Once a team has covered about 75% of a zone in their ink, the zone is "captured" by the team. When all of the zones have been captured by a team, that team is "in control" of the zones and their respective countdown clock begins to count down from 100. The opposing team must try to capture the zones in the same manner. After 5 minutes, the team who remains in control of the zone(s) and gets their countdown clock lowest wins a match; if a team's clock reaches 0, the game ends instantly as a knockout win for the winning team.

Controlling all of the zones causes the team's countdown clock to start. The team will lose control of a zone when 50% of it is covered in the opposing team's ink. Losing control of one or more zones causes the team's countdown clock to stop. If the opposing team then takes control of all of the zones, a penalty is given to the team that was previously in control. Upon retaking all zones with a penalty, the penalty clock will tick down first, before the team's main countdown timer resumes.

If the losing team has control of the zones as time runs out, then the match will go into overtime. The match ends once the losing team regains the lead, or the winning team regains control, or the zones remain uncontrolled for 10 continuous seconds.

The total time for a team to win a match after they control the zone without additional penalty or losing control is 60 seconds.

Overtime Rules
Overtime will begin if the losing team (with a higher timer count) has full control of all zones. At this point, Overtime will end when:

(Note that on maps where there are two Splat Zones, the winning team only needs to control one of the two Splat Zones to end the match.)
 * The losing team lowers their timer below the winning team's timer, thereby giving the losing team the victory.
 * The losing team loses control of the/a splat zone, and cannot regain control within 15 seconds.
 * The winning team retakes control of the Splat Zone.

In-game Info
"In Splat Zones teams battle for control of a stage's Splat Zones. Each stage has one or two zones. To gain control of a Splat Zone, just splatter it with ink! Once your team controls a zone, try to hold it for as long as possible. Your team's timer will start once you control all of the zones in a stage. If your timer reaches zero, your team wins! But if you lose control of a single zone, your team's timer will stop. There's also a penalty for losing control of all the zones to the enemy, so guard them with all your might! If the battle ends without a winner, the team with the lowest count on its timer will claim victory! In this ranked battle, Battle Points are awarded based on your timer. Oh, and here's a pro tip for ya: if you lose control of a Splat Zone, wait for your team to regroup instead of trying to be a hero!"

- In-game Info

Penalty
The penalty assigned to a team is dependent entirely on their own performance. The opposing team's progress is not taken into account.

The penalty for losing control of the zone is calculated as follows:

X = time remaining when team first captured the zone Y = time remaining when the zone was captured by the opposition

penalty = 0.75 × (X - Y) This value is rounded to the nearest integer and added to any existing penalty. if X = 100, 1 is added after rounding.

"Time remaining" is the sum of the main timer and any penalty in effect. The value of X is set when a team regains control of the point from an opponent, but not when regaining control of the point from its neutral state.

Demonstration
https://www.youtube.com/watch?v=Nv1VF_wzt8A

Trivia

 * Splat Zones bears a strong resemblance to Team Fortress 2's King of the Hill mode and Domination Control Point mode, where a team needs to capture a zone and their clock to countdown to zero in order to win the match. In Splatoon, there can be one or two zones to control and if you manage to recapture the zone from the other team, they get a penalty time added to their count.
 * A 'second' for the countdown timer in Splat Zones is actually around 0.625 (5/8) seconds in real time.