Mechanics Monday – Zone of Control Basics

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Today we’re taking a look at Zone of Control Basics. This is first of a two-part series. We’re going to cover what zones of control represent, how they are generally employed in this basics article. We will also look at some basics for how you might approach them in a game.

Let’s pay homage to the first formal written summary provided to us by SPI back in 1977 before we get started. SPI released an Introduction to Wargaming publication that covered many of the terms we still use regularly today in the hobby. There are still many concepts that find their roots in the first wargames released by Avalon Hill back in 1961 despite 50+ years of commercial board wargaming evolution:

Introduction to Wargaming Cover from SPI

Zone of Control

Excerpt from Zone of Control Gamespeak
Original Excerpt…

The area of effect surrounding a unit; usually defined as the six immediately adjacent hexes. In theory, the exact character of a Zone of Control in a given game-system may be delineated by the use of a combination of adjectives, taking one from each of the following groups:

Effects on Movement

  • Locking – Units must stop upon entering an Enemy controlled hex and may leave only at the beginning of a Movement phase.
  • Rigid – Units must stop upon entering an Enemy controlled hex and may leave only at the beginning of a Movement Phase.
  • Elastic – Units may enter and leave Enemy Zones of Control by paying an additional cost in Movement Points.
  • Open – Zones of Control have no effect on Movement.

Effects on Combat

  • Active – Requires that every Enemy unit in a Friendly Zone of Control be attacked in the Combat Phase.
  • Inactive – Makes no requirement for attack.

Effects on Supply Line and Retreat

  • Interdicting – Prohibits the path of retreat or supply from being traced through an Enemy Controlled hex regardless of the presence of Friendly units.’
  • Suppressive – Prohibits the path of supply or retreat from being traced through an Enemy controlled hex if the hex is not occupied by Friendly Units.
  • Permissive – Does not affect the path of supply or retreat in any way.

Modern wargames owe a lot to the visionary work of Jim Dunnigan who created, as Mark Herman has suggested, a “skill trades guild system” for developers and designers in the 1970’s. Dunnigan was visionary in the way he documented how SPI games worked, outside of the contribution to the games and designers. It’s probably why even the Department of Defense listened when he spoke. The summary presented in 1977 is as good an introduction today as it was then.

Mechanics vs. “Reality”

I won’t get into the debate over what is real or not. I will say that Zone of Control (ZOC) is used to help sustain the illusion of influence over distance. Wargames are frequently controlled by arbitrary boundaries. They might be hexes, squares, or even small geographic areas. So, it is frequently necessary to demonstrate the combat effectiveness of units beyond these “walls.”

Zone of Control is handled differently by almost every game. As a result, the SPI definition from 1977 is mostly good as an introduction. It doesn’t intend to be more, but nor should it be confused with the final word on the subject. Instead, we must look at the game itself and what it is trying to accomplish.

There are a few fundamental things that Zone of Control tends to express:

  • Sub-units – The units in strategic and operational level games are so large that often a ZOC rule helps flesh out the areas in which sub-units are deployed.
  • Mobility – The scale of a game’s individual turns and hex sizes may allow for units to exert “reactionary” control over a larger area.
  • Weapon Systems – The scale of the game’s hexes compared to the “reach” of the weapon and detection systems allows units to exert a much larger area of control.

As a Game Mechanic

Zone of Control adds depth to the tactical and strategic considerations a player must make. This is particularly true as you layer the effects of Zone of Control. A ZOC rule section that covers movement, supply, combat, and retreat rules makes a player’s awareness of the effects crucial to understanding the game.

All great wargame mechanics share a common theme. Malleability.


Zone of Control clearly fits theme of malleable. In fact, ZOCs have proven to be some of the most malleable rules in all of wargaming. We’ll be looking at the varied ways designers have employed ZOC in next Monday’s article.

Food for Thought

Here are a few things I always consider when a game presents me with ZOC rules:

  • How can I use Zone of Control to maximize my “front?”
    • Many games that employ ZOC expect players to incorporate the rules into the way they position their units. It is critical to figure out how to best use ZOC to take advantage of the rules. This is something to consider if your opponent is outflanking your lines.
  • Are there opportunities to force my opponent into an unfavorable position using Zone of Control?
    • ZOC typically creates severe penalties for retreating units. This often means additional step losses. You can also consider forcing units out of supply using ZOC since many supply rules do not allow supply lines to pass through an enemy controlled ZOC. This can be a subtle way to outfox your opponent since many wargamers (myself included) can be myopic when reviewing the board state.
  • Does the terrain allow me to create artificial bottlenecks using Zones of Control from my units?
    • Most wargames feature some sort of impassable terrain. That might be water, mountains, bogs, or countries through which units may not travel. So, finding ways to abut these areas with ZOC can create bottlenecks that wouldn’t otherwise exist. This is useful for blocking and for trapping opponents, especially when reaction movement is allowed.

Every wargame brings its own flavor to the core ZOC concept. As a result, understanding how each game designer expects players to interact with ZOC is key. Finding the secret of that interaction is one of the fun little “mini games” of the wargaming hobby.

Share your thoughts on SPI’s summary definition and your favorite ZOC tricks in the comments below!

Be sure to check back next Monday when we’ll be following up on this article with examples of unique ZOC concepts.

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2 Comments

  1. Nice analysis. Indeed, that mechanic is very often used in operational and tactical wargames. I had seen many concepts and incorporations – the nice things that you can use ZOC as part of your strategy and plans. Thanks for article!

    • Next week, we’ll be looking at some examples of different kinds of ZOC and a few thoughts on ways to use ZOC to your advantage.

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