The London Underground Map is one of the most iconic, and globally known designs. No matter where you are in the world, you are likely to use a map inspired by the Tube’s Map design if you happen to use public transportation. Given that it is merely an aid for finding your way through the Underground lines, the fact that it has become one of the most recognizable symbols of London (even for people who have never visited the city) is even more remarkable.
To appreciate the genius of its design and just how disruptive it was, we have to take a look at the map that preceded it.

The only thing notable in this older version of the Tube map is the distinct colors of different lines. Apart from that, it is a map like any other. Just as you had expected any map to look like in 1930. The basis for the map is a real, accurate, topological map of London at the time (mainly the central part of London). And that is the reason the Underground lines are “randomly” flowing on the map: it is an accurate representation of where the Tube lines are running in the real world.
To anyone who ever used a map, this seems like a reasonable design. But somewhat less so to Harry Beck, a young engineer who worked at the London Underground Signals Office. Beck realized that the rules that dictated how maps had been designed until then should not necessarily apply to a public transportation map, let alone an underground network of tunnels and stations.
While rules are important for consistency and efficiency, Beck started to work in his spare time on an alternative design — a design that redefined the known cartographic design rules. When he submitted his creation in 1931, it was rejected by his managers because it had broken the rules. One year later, thanks to Beck’s persistence, he managed to print and distribute 500 copies as a pilot. The reaction was so positive that in 1933 Beck’s map became the official map of the London Underground.

The secret of Beck’s creativity and the global success of his design lies in knowing how to play with rules.
Breaking the Rules
The first thing Harry Back did was intentionally break the most important rule of cartography: working with a map scale. A good map has a scale, and the scale should be used for drawing (and later reading) the sizes of areas and distances on the map. Beck realized that it was this rule that made the Underground map less usable. Some areas in central London had many stations very close to one another. But working with a scale that fit these areas meant that the map would have been too large, or some areas farther from the center would have to be omitted.

Beck’s design ignored scale. The distances between stations had nothing to do with the distances in the real world, and it was entirely inconsistent. By not using a predefined scale, Beck managed to include many more stations on the map while keeping it readable and usable.
Rules exist for a reason, so when you break a rule, you almost always sacrifice something. As we will soon see, you have to make a conscious decision as to what to sacrifice. Breaking rules is not the goal, but a means to simplify the challenge we need to address. Scarifying some details or qualities (in this case, the accuracy of the map) can help us find creative solutions. Breaking some of the rules expands our playground and, with it, the solution space. But Beck didn’t break all the rules. He kept using the color-coding of the Underground Lines, and he kept most of the symbols used. Why? Because, as we will see, these rules served a purpose.
That is the essence of any disruption: stripping the problem of some (or most) of the rules that affect the solution space and keeping only the essential ones that serve the goal. It is like watching the problem and the solution space through a lens that blurs the irrelevant rules and focuses you only on the core of the problem. The more mature the problem domain is, the harder it is to challenge the rules governing it. Common wisdom is the biggest obstacle to breaking the rules. And that is the reason Beck’s map was initially rejected — it was rejected by people who took the standard rules of cartography as the ultimate guidelines for achieving the goal.
Inventing New Rules
Harry Beck didn’t just wisely select which rules to break. He did much more than that: he added some new rules of his own to the game.
Rules are important. We might think that the fewer rules we have, the better, as the solution space will be limitless. In reality, however, setting some boundaries around our playground, even if they seem arbitrary at first, often helps us generating a creative outcome. Creativity and playing have much in common, and games should always have rules.
When Beck started to work on his version of the Underground map, he decided to use only horizontal, vertical, and diagonal lines at 45 degrees. This decision broke yet another rule of cartography. It implied that the map would be schematic and will not describe the actual route of the Tube lines. But at the same time, it added a constraint to the way the map was about to be drawn.
Rules, by definition, shrink the solution space. When they are added wisely, they help you focus and find an effective solution. What seems an arbitrary rule proved to be yet another pillar in the groundbreaking map design. By drawing all the lines on this predefined and limited grid, the outcome was neatly arranged, much more readable, and pleasant to look at and explore. The new rule that Beck had added to the game simplified the result. Beck’s modified set of rules turned out to be an opportunity to create a new kind of map — a map that was perfect for finding your way in a public transportation network.
Harry Beck saw a challenge and did not give in to the set of rules that, up until then, was set in stone. He realized that to achieve something different, let alone better, he had to reshape the rules. The genius of Beck’s design is in realizing which rules must be broken and which new rules should be added. Which brings us to the third pillar of manipulating rules.
Know What You Are Trying to Achieve
Reshaping the rules of the game — the boundaries of the playground — is not a random act. When you manipulate the rules, breaking some of them and inventing new ones, you need to have something to guide you. There should be a purpose for any such decision — rules should serve a goal. The way the goal is phrased and articulated affects which rules you can manipulate and to what extent.
If your goal is to create a map that will help you know the exact traveling distance from one point to another, you probably cannot break the scale rule (or you need to add another layer of information to the map, which might make it more cluttered). If you aim to describe the exact route of the tunnels for the maintenance crew to locate external infrastructure, limiting yourself to straight lines is probably not a good rule to follow. What Beck realized is that none of these goals are relevant to the audience of the Underground map. In fact, these goals are creating distractions.
For a person taking a Tube ride, the tunnel curves are meaningless, and so is the distance between stations. Nobody measures distances on the Underground map. The people taking the train don’t need to know there’s a left turn on the tracks. They just want to know at which station they should board the train, where to switch trains, and when to go back above ground.
By understanding what the map should really achieve, Beck realized which rules could be broken and which new rules are required. Any rule that didn’t serve the rephrased goal was ignored. Rules that promoted it were added. Scaling was ignored because it didn’t serve any purpose for the users. On the contrary, it introduced unnecessary complexity. A strict grid layout was added because it helped the users read the map more conveniently.
When you face a challenge and seek a creative solution, you must reshape the rules of the game. Doing so wisely requires you to carefully phrase what it is you are trying to achieve. How your goal is expressed impacts which rules you can break and which rules should be added. Disruption is not achieved by arbitrarily manipulating rules. It has to be directed by a purpose. When done right, people will find value in it.
The London Underground Map became an iconic design because Harry Beck managed to capture the essence of what people were looking for, even if they didn’t know how to articulate it. He then dared to invent a new playground and a new set of rules. He knew there was no chance to achieve what people were looking for without changing the game.