Chapter 6. World Types II: Space and Size

Where do the diverged world lines exist? With that question left behind by the rules of time, we move to the second axis: space. The space axis treats where a world is and how large it is. Everything from the type that stacks entire universes on top of one another to the type that is complete within a single house lies on this axis. The guiding question of this chapter is: how large must a world be? The conclusion, stated in advance: a world's size is measured not by the breadth of its stage but by the range across which its laws apply.

1. Parallel Universe: Worlds That Exist Side by Side

Begin with the largest spatial type. Parallel universe is the type that posits other universes existing alongside our own. Each universe is a complete world in itself, and the default state is that they do not interfere with one another. What this type offers a worldview, above all, is legitimate plurality. A different life for the same character, a different history for the same city, can coexist without contradiction. What would have been a paradox inside a single world becomes lawful the instant the universe is divided. A universe where Shakespeare lives in the modern day and a universe where he lives in the Joseon dynasty do not quarrel with each other. This is also why parallel universe is a favorite device for managing derivative versions. Declare a reboot and the old edition as separate universes, and the diverged versions each gain a quarantine zone. It is the formalized quarantine discussed earlier, realized as a spatial setting. The focus of the law is the wall between universes. If the wall is complete, each universe is only a setting to the others and never becomes a story. For a story to take shape, the wall needs a door, and the instant a door exists, a list of rules follows it: who can cross, what is preserved and what changes upon crossing, how the two universes' time corresponds to each other. The design implication is that it is not the number of universes but the rules of the door that determine the workload. Declare a hundred universes and it is still one sentence, but the rules for a single door are a full sheet. Declaring a universe with no door is cheap, and as cheap as it is, it carries no narrative value either. This type's entire budget should go to the door.

2. Branching Universe: Worlds That Split Off

Give parallel universe an originating mechanism and it becomes branching universe. In this model, the universes were not side by side from the start; instead, a world splits off at every fork of choice and event. If, in the time-axis rules, you chose the option in which a change gives birth to a new world line, you are already standing on this model. The appeal of branching universe is that causality becomes terrain. Since every universe departs from a common trunk, the difference between any two universes is simply a calculation of causality after their point of divergence. The design grammar of alternate history is, in effect, extended to the scale of universes; the technique of selecting a point of divergence and simulating its causal consequences is reused unchanged. This is also where the focus of management is set. The core document of a branching-universe worldview is not a setting bible per universe but the branch genealogy. The tree structure of where each branch split off, why, and what changed as a result becomes the map of the entire world. Branch without a genealogy to track it, and a state in which no one can trace which universe a given setting belongs to arrives quickly. The periodic grand-cleanup events that long-running shared franchises hold are the occasions on which this debt gets settled. The implication is to treat the issuing of a branch like a registration gate. A new universe looks free, but the cost of managing the correspondence it forms with the existing universes accrues permanently. A branch is not creative freedom but the issuance of debt, and managing the volume issued is this type's fiscal health. Every time a branch is made, the question to ask is how many stories this universe can carry.

3. Isekai: The World One Crosses Into

Put the door between universes at the center of the narrative, and the result is isekai fiction. It is the type in which a present-day character crosses over to live in another world; Japanese web novels standardized it, and Korea's dimensional-transport fiction and the regression-fiction family are its neighbors. The core of the structure is the gap. The protagonist arrives in the new world carrying the knowledge and sensibility of the original world, and the gap between the two worlds becomes the narrative's engine. The turn in which modern knowledge becomes a cheat code in a world of magic, and the comedy in which common sense on this side becomes nonsense on the other, are both products of that gap. Without the gap, crossing over has no meaning either; a protagonist who crosses into a place identical to the original world is given no story. So the design of isekai fiction is not made of the destination world alone but of the pairing of origin world and destination world. What is carried across matters as much as what kind of world the destination is. Depending on whether it is knowledge, a smartphone, physical ability, or memory that gets carried in, an entirely different story emerges even from the same destination. Bring in only knowledge and you get a story of cunning; bring in system privileges and you get a growth story, and so on. The rules of the gateway also split the type: is it one-way or round-trip, does dying send you back, does time flow at the same rate on both sides? The implication is to place the manifest of what is carried in and the conditions of return at the very top of the world's laws. These two clauses determine the total amount of tension, and they are also the clauses whose breach of contract sends the largest shockwave if changed midway. The instant a way home opens up in a world the story had declared impossible to leave, the entire settling-in narrative built up to that point is shaken retroactively.

4. Game World: A World Where the Rules Are Exposed

The most common destination chosen for isekai is the game world: a status window pops up, levels and skills exist, and the world's rules are exposed as numbers. The idea of a game-like world splits into virtual-reality fiction and status-window fiction, but the worldview structure is the same: above the world's physical laws sits one further layer of superior rules called the system. The relationship between the two layers — that is, how far the system overwrites physics — is this world's first setting. This type's strength is that the exposure of rules is itself a device of verisimilitude. Because the system of power is disclosed in numbers, no dispute arises over who is stronger or weaker, and because the stages of growth are stated explicitly, the protagonist's power-ups are not judged as deus ex machina. Readers already know the system's grammar from game experience, so the cost of learning it is nearly nothing; an entire generation raised on games is this type's pool of ready-made readers. But the weakness, too, comes from the exposure of rules. A number can be checked. A twist that overturns a level gap, a protagonist who becomes an exception to the system, are staples of this type, but if the exception's grounds are not laid out inside the system, the entire world is judged as convenience. The implication is writing a system spec. The definition of stats, the growth curve, and the exception clauses must be fixed to the standard of a game design document, and in particular, which clause of the system will justify the exception granted to the protagonist must be designed in advance. Devices such as the hidden class and the unique job are all techniques for legalizing an exception by reclaiming it back inside the system.

5. Small Worlds: A World Need Not Be Large

Now turn the gaze that has been stacking universes toward the opposite extreme. The word worldview commonly conjures a continental map and a thousand-year chronology, but a world need not be large. A single school, a single company, a single house can all be a complete world. The grounds for this lie in the definition of a world. What makes a world a world is not its area but the existence of laws proper to it. If there are rules, a hierarchy of status, taboos and customs, and slang and common sense that hold only inside it, that range is already one world. A school has the school's law, and that law does not hold outside the school gate. The clearer the boundary where it stops holding, the clearer the world's outline. This view, that the range across which laws apply is precisely the size of the world, overturns two things in practice. First, worldview work for a small world is not a scaled-down copy of work for a large world. Relationships and norms, not geography and chronology, become the body of the document, and the workload is by no means smaller — a continental map is simply replaced by a character relationship chart, a dynastic chronology by an academic calendar. Second, the standard for density changes. A large world tolerates sparse density, but in a small world every region is a thoroughfare of the story, so detail is demanded all the way into the corners. In a world the size of a single room, every object in that room is a setting. This inverse relationship, in which the demand for resolution rises as size shrinks, is the budget formula for designing a small world. The four topics that follow examine representative small worlds in order, under this view, moving from the large toward the small.

6. Village and City: The Density of Space

The first unit of a small world is the village or the city — a community smaller than a nation and larger than a building, a scale that can be grasped on foot. The asset proper to this scale is density. In a nation-sized world, place names are a list; in a village-sized world, every place name becomes a scene. Every alley has its history, every shop has its owner's circumstances, and the residents know one another. It also means it is a space where a newcomer or an outsider is identified immediately. The condition of knowing one another is this type's law engine. In a space with no anonymity, rumor is the medium, reputation is the currency, and the past does not disappear. The difference between city fiction and village fiction is also a difference in the concentration of this same condition. A city is a space where anonymity and community mix, so it becomes a multilayered world with different laws in each district; a village is a space with anonymity removed, so a single web of relationships becomes the entire world. The design implication is that the character of the map changes. A map at this scale is less a topographic map than a relationship chart. Which house is in-laws with which, which house is a sworn enemy of which, which shop is where a given rumor collects — these stand in for the placement of mountain ranges and rivers. The terrain does not change, but relationships change with every event, so this map becomes a living document with a short update cycle. And securing a few constants of the space — the bridge everyone crosses, the square where everyone gathers — lets the stage of events converge there naturally, unifying the world's impression. A location that recurs is banked in the reader's memory as the world's landmark.

7. School and Club: The Grammar of a Closed Society

Go one layer deeper than the village, and there is the school. The school is the royal road of small worlds, the stage of the vast genre of coming-of-age fiction. The first trait the school has as a world is a built-in clock. Enrollment and graduation, the beginning and the end, are fixed into the institution, so the world itself is finite. The three-year time limit lays a mood of deadline under every event, and the school year and its seasonal events set the world's calendar in the story's place. From the entrance ceremony to the graduation ceremony, the beginning and end of the story are, in effect, already inscribed into the world. The second trait is a fully equipped class system. The hierarchy of grade levels, the two-tier structure of teacher and student, even the pecking order inside a classroom — a scale model of society is already installed. What the designer builds is not the system but the system's local variant: the special rules that belong to this school alone. A club or a circle is a world inside the school, a doubly small world. It has a door of joining and leaving, a territory called the club room, and its own law called tradition. This structure of building a still more closed room inside a closed room is the standard technique for raising the density of belonging. It is also common for a single club room to become the stage of the main story while the school as a whole recedes into background. The implication is that a school story's worldview document compresses down to an annual calendar and a table of rule variants. Fix the order of events and a few institutions unique to this school, and the world's skeleton stands. What remains is the web of character relationships that will bring that skeleton to life, and that holds true at the next scale as well. The frame of the school is also universal, which makes it a world that exports without translation.

8. Company: The Organization as a World

The next world that characters enter after graduating from school is the company. The company, stage of office fiction, is a closed society resembling the school, but the composition of its laws is different. If belonging at school is a matter of status, belonging at a company is a matter of contract. The fact that joining and leaving are always possible is laid into the floor of this world, so staying and leaving themselves become an ongoing narrative. That the single word resignation is a dramatic device unique to this world follows from this. The hierarchy also operates differently. A grade level is advanced automatically by time, but a job title is won through competition. Institutions of promotion, personnel transfer, and performance review stand in for the world's seasons, and the organization chart is this world's map. Part of this world's grammar is that behind the official organization chart lies an overlapping, unofficial one made of real power and factional lines. Reading the gap between the two organization charts is this world's residents' survival skill, and the reader's point of interest as a spectator. Another constant of office fiction is the repeated crossing of the boundary. Through commuting in and commuting out, characters enter and exit the world every day. Because a life outside the world runs alongside it constantly, this world's seal is weaker than the school's, but in exchange it can use the contrast between inside and outside. The implication is that the choice of industry is half the world. The frame of company is shared, but a hospital, a broadcaster, and a game studio each bring different specialized laws and burdens of accuracy. An organization chart, the rules of review and promotion, and procedures unique to the industry — these three form the spec list for designing a company world. Add to this a list of unofficial spaces such as the break room and the smoking area, and the world gains room to breathe.

9. Home: The Smallest World

The final scale is home. A few members, and the space is a single house. Physically the smallest of these worlds, it is nevertheless the strongest world by the intensity of its laws. The grammar of family fiction is the evidence. A home has no written law; customary law is all there is. Who sits where at the dinner table, what can and cannot be said, a conversation that has been postponed for years, the recurring ritual of the holidays — none of it is documented, yet every member knows these rules exactly. The character of belonging is also extreme. One graduates from school and one resigns from a company, but leaving a family is not institutionalized. This absence of an emergency exit, in which the relationship does not dissolve even if a member leaves, is what generates a home narrative's pressure. It is a world where even a severed tie remains one form of the relationship. A confined space, few people, and no possibility of escape is also a combination the theater has long loved. There are two design implications. First, the setting of a home world is carried by objects. Things with a history — an old sofa, a father's chair, a locked drawer — are this world's relics and its documents; the prop list becomes the setting bible. The smaller the item, things like ownership of the remote control or an assigned seat at the dinner table, the more it functions in this world as a map of power. Second, this world's timeline is woven not from events but from silences. How long a thing has gone unmentioned decides the world's structure as much as what the thing was. This list, worth calling a chronology of taboo, is the home world's hidden setting bible. The smallest world demands the most precise design.

10. The Boundary of the World: How Far to Design

Having come down now from the universe to the home, one last question remains on the space axis. Whichever scale is chosen, design must have an end. This is the question of the world's boundary — where to stop building. The principle has already appeared, in the principle of detail. The thoroughfares the story will pass through are the mandatory stretch, and everything beyond is the optional stretch. Applied to space, it works out as follows: the basic scope of design extends to the maximum radius the camera can reach, plus one layer of margin. In a school story, the school, the route to and from it, and the regular snack shop are mandatory, while the administrative district of the next city over is optional. The judgment that spending on the optional stretch while leaving the mandatory stretch empty is mere play still holds here. The reason for leaving one layer of margin is that the story tends to leak a little further outward than planned. A technique for handling the boundary is also needed. Leave the far side of the boundary a complete blank, and the world thins out like a stage set. The solution is the low-resolution beyond. Let what lies past the boundary exist only at the low resolution of place names and rumor, and it creates a natural sense of perspective against the dense interior. What is far away is normally blurred, so the reader reads low resolution not as incompleteness but as distance. A war in the north that exists only as rumor, an empire across the sea that exists only as a name, make the world look larger than it actually is. And this blurred beyond remains a reserve for expansion. A sequel usually begins with a single place name from beyond the boundary gaining resolution. The low-resolution beyond is worth registering in the document as a reserve for future content. The boundary is not the end of the world but the starting line of the next one.