GEO Fundamentals Complete Guide — AI Search Optimization for Japanese Companies
An introductory text that unpacks the definition of Generative Engine Optimization (GEO), how it differs from traditional SEO, and the current state of the Japanese market using observed data from smoke analysis.
GEO Meter editorial team·8 min read
Executive Summary
GEO (Generative Engine Optimization) is the practice of getting "cited" by generative AI search engines such as Claude, ChatGPT, and Gemini. It is more accurate to think of it as a different game rather than an extension of traditional SEO.
The years 2025-2026 mark the dawn of the domestic market. Companies that take action early are more likely to dominate the top of industry rankings.
According to GEO Meter's smoke analysis data (2 topics x roughly 20 domains), the companies cited by AI share three traits: (1) deployment of llms.txt, (2) implementation of structured data (Schema.org), and (3) FAQ-style body structure.
This article organizes the definition of GEO, how it differs from SEO, the state of the market, and what your company should tackle first.
1. The Definition of GEO
GEO (Generative Engine Optimization) is the umbrella term for optimization practices aimed at getting your company's information cited and recommended by generative AI search engines such as ChatGPT, Claude, Gemini, and Perplexity.
A similar concept, AEO (Answer Engine Optimization), is often used as a near-synonym, but the industry is increasingly adopting GEO as the broader term.
The core of GEO comes down to these three points:
A structure AI can read easily (Schema.org JSON-LD, FAQs, clear heading hierarchy)
Optimization for AI crawlers (llms.txt, AI-bot accommodation in robots.txt)
Signals of authority (first-party data, explicit sources, regular updates)
2. How It Differs from SEO
GEO and SEO differ in goals, metrics, and tactics. The table below contrasts them.
Aspect
SEO (traditional)
GEO (new)
Goal
High ranking on search result pages
Citation and recommendation in AI search
Target engines
Google / Bing
Claude / ChatGPT / Gemini / Perplexity, etc. (GEO Meter currently observes three AIs: Claude / ChatGPT / Gemini)
Structuring, AI-friendly interpretability, primary information
Measurement
Google Search Console, Ahrefs
AI citation observation tools such as GEO Meter
Impact of update frequency
Medium (several months of lag)
High (changes within weeks)
3. Why GEO, Why Now
3.1 Rapid Market Growth
ChatGPT's user count surpassed 200 million in 2024, and Perplexity and SearchGPT are also growing rapidly. The shift from "searching on Google" to "asking an AI" is progressing, especially in the B2B space.
3.2 The Domestic Market Is at Dawn — First-Mover Advantage
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2026 is likely "the last window for first movers to seize industry rankings." In 1-2 years, most companies will have implemented measures, making top positions hard to win.
3.3 SaaS / B2B Purchasing Behavior Has Changed
Surveys of B2B purchasing decision-makers show a growing share use AI chat as the first step in product research. If your company isn't cited for a query like "recommended XX service," it doesn't even reach the consideration set.
4. What Smoke Analysis (2 Topics x Roughly 20 Domains) Reveals About Companies Cited by AI
In GEO Meter's smoke analysis conducted in April-May 2026 (2 topics x roughly 20 domains), we compared the structural differences between the top citation group and the bottom citation group.
Differences actually observed in the smoke analysis:
Observation metric
Top group
Bottom group
Difference
Topic
llms.txt deployment
40%
10%
+30pp
Otaku travel
llms.txt deployment
20%
0%
+20pp
Fat reduction
og:title configured
85.71%
60%
+25.71pp
Fat reduction
Observational tendencies (quantification is future work):
Schema.org JSON-LD implementation rate tends to be higher in the top group
FAQ page possession is also notable in the top group
sitemap.xml is a standard implementation deployed by virtually all companies
In particular, the gap in llms.txt deployment is vivid — the top group consistently exceeds the bottom group by 20-30pp. llms.txt itself has low implementation cost, making it the first measure you should tackle. Detailed analysis and per-industry numbers will continue to be updated as we expand the observation set.
5. Where to Start in Your Own Company
GEO tactics span many areas, but it's important to clarify priorities and work through them one at a time. The recommended order from GEO Meter:
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5.1 Start with Observation (Free Diagnostic)
"Adding measures without knowing what the problem is" is the most inefficient approach. Grasp the current state, then improve from the weakest point is the standard play.