# Core and outer sections: the two halves of a topical map

Every topical map has two halves: the pages that make you money and the pages that explain your subject. Here is how to split them, how they connect, and what a real split looks like.

By Kevin Jeppesen, AI growth engineer. Founder, FrameworkSEO & Ascendily. Updated 2026-11-13. Source: https://frameworkseo.com/learn/semantic-seo/core-and-outer-sections

**Core section and outer section:** In Koray Tuğberk Gübür's topical map framework, the core section is the set of pages tied to how a site makes money, and the outer section is the wider set of pages on the same subject that support them and link into them.

## Key takeaways

- The core section holds the pages where a visitor can pay you, book you, sign up or click the link that earns you money; the outer section holds every other page on the same subject.
- A site built only from pages that sell has few ways in, and a site built only from blog posts gets readers it cannot sell to; the map needs both, linked.
- In 106 topical maps we delivered, the median share of pages that sell was 19%, and the outer section was the bigger half in 102 of them.
- In two real maps we checked, every outer page reached a page that sells within two links; an outer page that cannot do that has no purpose and should be merged or removed.
- The split is Koray Tuğberk Gübür's planning model, not a Google term: site-level quality has support in Google's own court records, but no controlled test shows outer pages lifting the pages they link to.

## What the core section and the outer section are

The core section is every page in a [topical map](https://frameworkseo.com/learn/topical-maps/what-is-a-topical-map) that is tied to how the site makes money. For a store that is the collections and products. For a plumber it is the service pages and the town pages. The outer section is every other page on the same subject: the guides, comparisons and answers that explain it.

The two names come from [Koray Tuğberk Gübür's framework](https://frameworkseo.com/learn/semantic-seo/koray-topical-map-framework). He lists five parts of a map: the source context, the central entity, the central search intent, the core section and the outer section. The first three decide the last two. In [his 2023 article on expanding a topical map](https://www.holisticseo.digital/seo-research-study/topical-map), he writes that the source context determines "the topical map's core and outer sections".

So the line is not drawn by page type. It is drawn by money. Work out your [source context](https://frameworkseo.com/learn/semantic-seo/source-context-central-entity) first, meaning why your site exists and how it earns. The pages closest to that earning are the core. Everything that teaches the subject around it is outer.

![A topical map as two rings around one subject: collections that sell inside, guides outside, each guide linking inward.](https://frameworkseo.com/learn/core-and-outer-sections/two-halves.webp)

*The core sits close to the money; the outer section surrounds it and every outer page points inward.*

A simple picture helps. Think of a shop on a busy street. The core is the counter where people pay. The outer section is the shop window, the advice the staff give, the leaflet someone takes home. Nobody pays at the window, but most people who reach the counter walked past it first.

> **Google reads this term as land maps:** On 13 November 2026, all 20 of Google's top organic results in the US for "core section outer section topical map" were topographic map pages, school lab sheets and county elevation maps. Only the longer search "topical map core and outer section" brought up pages about SEO. These are working terms from one practitioner's method, not words Google uses.

## Why a site built from only one half stalls

A site with only pages that sell asks each page to win a buying search on its own. A site with only blog posts can win readers and still earn nothing, because no page sends them anywhere they can buy. Each half covers what the other cannot.

![Three site shapes: only selling pages, only blog posts, and blog posts linked into the selling pages.](https://frameworkseo.com/learn/core-and-outer-sections/three-shapes.webp)

*Only selling pages means few ways in; only posts means traffic with nowhere to go; linked halves give many ways in that all lead somewhere.*

### Only pages that sell

A store with 40 collection pages and nothing else has 40 ways to be found. Each one competes for searches like "oversized graphic tees", where every big retailer competes too. Nothing on the site meets the person who is still asking "what is a boxy tee?" three weeks before they buy.

Koray's own explanation, in a [LinkedIn post from August 2025](https://www.linkedin.com/posts/koray-tugberk-gubur_outer-section-of-topical-maps-why-it-matters-activity-7361187658343006208-QnWP), is that ranking signals gather in the core. The outer section builds authority over time, as the site gathers history: impressions, clicks and searches answered well.

### Only blog posts

The opposite site is common too. I see it most on sites that worked with an agency paid by the post. Those agencies just worked to publish as much as possible, because that's what was in the retainer. That's not how SEO is done properly. The posts get read, and nothing sends the reader on to a page that sells.

### What Google's own records say about the two halves

The split lines up with how Google described its own ranking under legal process. In notes of a 2025 interview filed in the US antitrust case ([exhibit PXR0356](https://www.justice.gov/atr/media/1398871/dl)), Google engineer HJ Kim describes two parts. Topicality is judged per query, from anchors, the page's body and clicks. Quality is "largely static and largely related to the site rather than the query".

Read that against the two halves. A page that sells has to win topicality for its buying search by itself; no guide can do that for it. What the outer section can change is the site-level part, and the links it sends. That is our reading of the record, not something Google has said about topical maps.

## Where to draw the line for a store, a service, software and a publisher

Draw the line at the page where a visitor can pay you, book you, sign up, or click the link that earns you money. Those pages, and the hub pages that group them, are core. Every page that explains, compares or answers questions on the same subject is outer.

| Business | Core section | Outer section | A bridge between them |
| --- | --- | --- | --- |
| **Store** | Collections, product pages, the main category | Style, fit and care guides; comparisons; size help | "How to shrink a shirt" links to the heavyweight T-shirts collection |
| **Service business** | Service pages, town pages, the quote or booking page | Cost guides, "what to do first" guides, insurance questions | "How to tell if a pipe burst" links to burst pipe cleanup |
| **Software** | Feature pages, use-case pages, pricing, the sign-up page | The jobs the software does, explained without the software | A guide to running a weekly team meeting links to the meeting notes feature |
| **Publisher or affiliate site** | The pages that earn the most per visit: affiliate comparisons, the topics with the best paying ads | Background explainers and news around those topics | "How mattress firmness is measured" links to the best mattresses comparison |

The software and publisher bridges in the table are made up, to show the shape. The store and service ones are real rows from maps we delivered.

![Three-question test: sells means core, reaches a selling page in two links means outer, otherwise merge or remove.](https://frameworkseo.com/learn/core-and-outer-sections/one-test.webp)

*Ask the questions in order; a page that fails the second one is the off-topic page this lesson ends on.*

### The publisher case most guides get wrong

Most explanations define the core as commercial page types: products, services, locations. That breaks for a publisher. When we counted the page types in our delivered maps, 11 of 106 had under 3% product, service or location pages. They were publishers, affiliate comparison sites and authors.

Their core is real. It is just made of articles: the comparisons that carry affiliate links, the topics with the best paying ads, the book pages. Koray describes the same move on a lifestyle publisher, TheCoolist.com, where the homepage was changed for "Source Context Re-definition, by re-adjusting the core of the website" (his 2023 article).

### Software, and stores with a wide subject

Software is where the outer section grows furthest from the product. Koray's Kanbanize.com case, a Kanban board tool, expanded from "Kanban Charts" into "Task Management", "Team Management" and "Business Efficiency", by his account. For stores, his Snuffstore.de case added product definitions and smoking alternatives around the product pages, and he reports 1,200%+ organic growth year on year over three months. Those are his reported numbers from his own screenshots, not audited figures. The store side has its own lesson: [topical maps for ecommerce stores](https://frameworkseo.com/learn/topical-maps/topical-map-for-ecommerce).

## How outer pages link into the core: contextual bridges

An outer page links into the core through a contextual bridge: a link in the body text, at the point where the idea on the outer page leads straight to a page that sells. The test is whether a reader of that paragraph would want that page next.

Koray named the concept. In his words, "without a proper contextual bridge, the internal links can't pass relevance, or PageRank in the context of topic-sensitive PageRank iterations". In [his 2023 SaaS guide](https://www.holisticseo.digital/seo-research-study/saas) he states the rule plainly: "All the topical map nodes should be connected to the conversion points and landing pages to support them with link flow."

### A bridge is information scent

There is an older idea from usability research that says the same thing from the reader's side. Information foraging theory, from Peter Pirolli and Stuart Card at Xerox PARC in 1999, says people pick their next page from the cues around a link. Nielsen Norman Group calls those cues [information scent](https://www.nngroup.com/articles/information-scent/): a reader's estimate of what the next page holds and what it costs to get there.

That gives you a working check for every bridge. A paragraph about shrinking a cotton shirt has strong scent toward heavyweight T-shirts, because heavier cotton is the fix. It has no scent toward graphic hoodies. Same store, same map, but only the first link is a bridge.

### What the bridges looked like in two real maps

I checked the links in the two maps whose rows appear later in this lesson. In the store map, 172 of the 237 outer pages link straight to a collection. The other 65 reach one in two links, through a hub page. In the service map, 108 of 122 outer pages link straight to a service or town page, and the other 14 do it in two.Not one outer page in either map is more than two links from a page that sells.

- Put the bridge in the body, in the paragraph where the reader is ready for it.
- Use the target page's own name as the link words, the same words every time. The full rules are in [internal links inside a topical map](https://frameworkseo.com/learn/topical-maps/internal-links-in-a-topical-map).
- Link up to the hub of a group as well when there is one, which is where [pillar pages](https://frameworkseo.com/learn/topical-maps/pillar-pages) sit.
- Write each outer page so the bridge belongs there. Turning the map into linked pages is the job of a [semantic content network](https://frameworkseo.com/learn/semantic-seo/semantic-content-network).

> **A footer link is not a bridge:** A link to your best collection in the footer sits on every page, including the ones with nothing to do with it. It has no paragraph around it and no scent. Bridges live in the body of the page that earns them.

## How big each half should be, and what decides it

There is no right ratio between the two halves. The core is as big as what you sell, times the ways people search for it. The outer section is as big as the subject around it. In practice the outer section is almost always the bigger half.

On 13 November 2026 I counted the page types in the 106 topical maps we delivered to paying buyers in October and November 2026. I counted collection, product, service, location (town) and pricing pages as pages that sell.

![Bar chart of 106 delivered maps by share of selling pages; most fall between 10 and 19 percent.](https://frameworkseo.com/learn/core-and-outer-sections/selling-share.webp)

*Median 19%; only 4 of 106 maps had pages that sell as half or more of the map.*

| What we counted | Result |
| --- | --- |
| Median share of pages that sell | 19% |
| Middle half of the maps | 11% to 33% |
| Maps where the outer section was the bigger half | 102 of 106 |
| Maps with under 3% pages that sell | 11 (publishers, affiliate sites, authors) |
| The store map shown below | 35% (137 of 391 pages) |
| The service map shown below | 24% (42 of 173 pages) |

Two things push the core up. A store with many product types gets a collection for each, which is why the store map sits at 35%. A service business that serves many towns gets a page per town with real local facts. Two things push the outer section up: a subject with many questions around it, and a buyer who researches for weeks before paying.

The whole map has no right size either. Our maps run from about 50 pages to over 20,000, depending on the size of the company, its subject and how many services it has. The median growth plan on 5 November 2026 was 159 pages. When the first pages are live and you add more, the order of what to add is covered in [expanding a topical map](https://frameworkseo.com/learn/topical-maps/expanding-a-topical-map).

## What goes live first: the core early, the outer around it

The pages that sell go live early, because every bridge needs a page to point at. Outer pages follow in groups, each one linking to a core page that already exists. The full method, with the reasons, is in [publishing order](https://frameworkseo.com/learn/topical-maps/publishing-order).

The two real maps show the pattern. In the store map, 15 of the first 20 pages to publish are collections. The middle core page goes live at position 178, the middle outer page at 230. In the service map, 12 of the first 20 are service or town pages, and the middle positions are 40 for core and 110 for outer.

Early does not mean alone. Some outer pages go live in the first weeks too, when they answer a question buyers ask right before they pay, such as a cost guide.

## A worked split: one branch of a real store map

In one real store map, the graphic tees branch splits into six collections that sell and six pages that explain: a style hub, three guides and two comparisons. Each explaining page links to the collection that sells what it talks about.

The map belongs to a US apparel store and runs to 391 pages. The rows are copied from it, anonymized; no title in them names the store.

| Publish | Page | Half | Searches a month | Bridge to |
| --- | --- | --- | --- | --- |
| 1 | Graphic tees: funny, weird and vintage statement T-shirts | Core | 201,000 | (top of the map) |
| 2 | Oversized graphic tees | Core | 22,200 | Graphic tees |
| 3 | Vintage and retro graphic tees | Core | 14,800 | Graphic tees |
| 4 | Graphic hoodies | Core | 40,500 | Graphic tees |
| 83 | Graphic tees for women | Core | 18,100 | Graphic tees |
| 86 | Heavyweight graphic T-shirts | Core | 9,900 | Graphic tees |
| 145 | 90s outfits: how to dress the decade today | Outer | 110,000 | Vintage and retro graphic tees |
| 202 | How to wear it: style, fit and care guides | Outer (hub) | 720 | Graphic tees |
| 203 | How to style an oversized T-shirt | Outer | 720 | Oversized graphic tees |
| 204 | How to shrink a shirt (and how to unshrink one) | Outer | 18,100 | Heavyweight graphic T-shirts |
| 329 | Heavyweight vs regular T-shirts: GSM, fit and feel | Outer | 390 | Heavyweight graphic T-shirts |
| 341 | What is a boxy tee? Boxy vs oversized T-shirts | Outer | 320 | Oversized graphic tees |

![A real store map branch: three collections, each with the guides that link up to it.](https://frameworkseo.com/learn/core-and-outer-sections/store-branch.webp)

*Search volume does not decide the half: 90s outfits has 110,000 searches a month and is still outer, because nobody buys on that page.*

### Three things the branch shows

- **The biggest search is not always core.** "90s outfits" draws 110,000 searches a month, five times the oversized collection. It is outer, and its job is to send readers to the vintage collection.
- **Small outer pages still earn their place.** The boxy tee comparison answers a search of 320 a month. It sits right before a purchase decision and links to the oversized collection.
- **The core goes first.** All six collections are in the first 86 positions; the explaining pages start at 145.

### The same split for a service business

The second map is for a US water and fire damage restoration company, 173 pages. Its water damage branch has six service pages in the core: restoration, cleanup, flooded basements, burst pipes, repair and mitigation. Around them sit eight outer pages, each tied to one service. "How to tell if a pipe burst in your house" links to burst pipe cleanup. "Dehumidifier for water damage: how long to run it" links to water mitigation.

One outer page there shows the two-link rule at work. "Does homeowners insurance cover water damage?" links to an insurance help hub, and that hub links on to the service pages.

[Download the core and outer worksheet](https://frameworkseo.com/learn/core-and-outer-sections/core-outer-split-worksheet.csv) (CSV: all 26 rows from both real maps with their half, bridge and two-link check, plus empty rows for your own pages)

## Every page needs a purpose: outer pages with no path to the core

An outer page that cannot reach a page that sells within two links has no purpose on the site. It is an off topic page, even if the subject sounds close. Try to merge it into a more relevant page first, and remove it only when nothing can use it.

I say this to every client who comes to us from another agency. SEO is about making sure the website is a quality website and every single page has a purpose on it. If a page does not have a purpose, it does not deserve to be on the website.

Koray made the same point in 2023: "An irrelevant and discordant topical map with irrelevant contexts and meaningless connections causes quality score demotion", by his reading of search engines. Google's [helpful content guidance](https://developers.google.com/search/docs/fundamentals/creating-helpful-content) asks a related question of site owners: "Does your site have a primary purpose or focus?"

The closest thing on Google's side is in its internal documentation that leaked in 2024. A record named [QualityAuthorityTopicEmbeddingsVersionedItem](https://hexdocs.pm/google_api_content_warehouse/0.4.0/GoogleApi.ContentWarehouse.V1.Model.QualityAuthorityTopicEmbeddingsVersionedItem.html) has a field called siteFocusScore, "how much a site is focused on one topic", and one called siteRadius, "how far page_embeddings deviate from the site_embedding". Google [confirmed the documents are real](https://www.theverge.com/2024/5/29/24167407/google-search-algorithm-documents-leak-confirmation) and warned against "inaccurate assumptions". The fields exist; how much they weigh is not public.

### How to check a site you already have

1. List every page and mark the ones where a visitor can pay, book, sign up or click your money link.
2. For every other page, follow its body links. Does it reach a marked page in one or two links?
3. For each page that does not, look for the more relevant page it could become a section of.
4. Merge it there and redirect its address. Remove it only when no page can use what it says.

The merge-first steps, redirects and what to watch afterwards are covered in [pruning, merging and updating](https://frameworkseo.com/learn/topical-maps/pruning-and-merging).

> **An off-topic page that sounds on topic:** A made-up plumbing company publishes "The history of indoor plumbing in ancient Rome". It is about plumbing. But no reader of it wants a boiler repair next, so no bridge fits, and it fails the second question of the test. A page on "why old lead pipes need replacing" covers similar ground and links straight to the pipe replacement service.

## What is Koray's model, what is our practice, and what has independent support

The split is a planning model from Koray Tuğberk Gübür, not a Google term. Some of the reasoning behind it has support in Google's own records. Some of it is his interpretation. One controlled test cuts against the most repeated claim about it.

| Claim | Who says it | What backs it | Status |
| --- | --- | --- | --- |
| A map splits into a core and an outer section | Koray (2023 article, 2025 post) | His case studies, his reported numbers | A planning model |
| Quality is judged for the whole site, not page by page | Google, under legal process | HJ Kim interview notes, PXR0356 (2025) | Supported |
| Clicks feed ranking | Google, under legal process | Judge Mehta's 2024 opinion: Navboost "pairs queries and documents through memorizing user click data" | Supported, per query and page |
| Click history on outer pages lifts the core | Koray (2025 post) | No public test | His interpretation |
| Links from outer pages lift the pages they point to | Koray (2023); most SEO guides | A 2021 SearchPilot split test of added related article links: linking pages gained 16%, linked-to pages showed "no detectable impact" | Not shown in the one controlled test |
| Pages far from the site's focus can hurt it | Koray (2023); us | siteFocusScore and siteRadius exist in leaked Google records; weight unknown | Plausible, not proven |
| Every outer page should reach the core within two links | Our practice | Held in both real maps checked above | Our rule, measured on our maps |

The SearchPilot result deserves a plain reading. It was one site, and the page count was not published. It does not prove bridges are useless. It does mean the confident line in most guides, that outer pages "route authority" to the core, has no controlled evidence behind it yet. One more leaked field fits Koray's idea without proving it: in [PerDocData](https://hexdocs.pm/google_api_content_warehouse/0.4.0/GoogleApi.ContentWarehouse.V1.Model.PerDocData.html), onsiteProminence "measures the importance of the document within its site". It is computed by sending simulated traffic out from the homepage and from pages with many clicks.

So I keep the split for a reason that needs no ranking theory. A reader who lands on a guide should be one click from what you sell. If the ranking theory is right as well, the map gains twice.

## Sources

- [How to Expand a Topical Map for Higher Topical Authority?](https://www.holisticseo.digital/seo-research-study/topical-map), Koray Tuğberk Gübür, Holistic SEO, 2023
- [SaaS SEO Strategies, Guideline, and Case Study](https://www.holisticseo.digital/seo-research-study/saas), Koray Tuğberk Gübür, Holistic SEO, 2023
- [Outer section of topical maps: why it matters](https://www.linkedin.com/posts/koray-tugberk-gubur_outer-section-of-topical-maps-why-it-matters-activity-7361187658343006208-QnWP), Koray Tuğberk Gübür, LinkedIn, 2025
- [Interview with H.J. Kim notes, remedies exhibit PXR0356, US v. Google](https://www.justice.gov/atr/media/1398871/dl), U.S. Department of Justice, 2025
- [Memorandum opinion (liability), US v. Google LLC, 1:20-cv-03010](https://storage.courtlistener.com/recap/gov.uscourts.dcd.223205/gov.uscourts.dcd.223205.1033.0.pdf), U.S. District Court for the District of Columbia, 2024
- [QualityAuthorityTopicEmbeddingsVersionedItem (leaked Content Warehouse documentation)](https://hexdocs.pm/google_api_content_warehouse/0.4.0/GoogleApi.ContentWarehouse.V1.Model.QualityAuthorityTopicEmbeddingsVersionedItem.html), google_api_content_warehouse v0.4.0, hexdocs, 2024
- [PerDocData (leaked Content Warehouse documentation)](https://hexdocs.pm/google_api_content_warehouse/0.4.0/GoogleApi.ContentWarehouse.V1.Model.PerDocData.html), google_api_content_warehouse v0.4.0, hexdocs, 2024
- [Google confirms the leaked Search documents are real](https://www.theverge.com/2024/5/29/24167407/google-search-algorithm-documents-leak-confirmation), The Verge, 2024
- [Information Scent: How Users Decide Where to Go Next](https://www.nngroup.com/articles/information-scent/), Nielsen Norman Group, 2020
- [Creating helpful, reliable, people-first content](https://developers.google.com/search/docs/fundamentals/creating-helpful-content), Google Search Central, 2026