- Introduction: The Importance of SEO in Japan’s Digital Ecosystem
- What Was WELQ?
- The SEO Strategy Behind WELQ
- Public Backlash and Media Exposure
- DeNA’s Response: Site Closures and Official Apology
- The Long-Term Impact on Japanese SEO
- What Global Marketers Must Understand About Japanese SEO in the Age of AI
The Importance of SEO in Japan’s Digital Ecosystem
In Japan, SEO (Search Engine Optimization) is a crucial element of digital marketing, just as it is in other countries. Especially in the mid-2010s, achieving high rankings on Google had a direct and powerful influence on a company’s business success. During this period, curation media—websites that compile and summarize information from various sources—became increasingly popular in the Japanese market.
This popularity was driven by Japanese users’ preference for comprehensive, easy-to-understand content. Curation sites catered to this demand by presenting complex information in simplified formats. From the business side, text-heavy content was well-suited for SEO, and using external writers gave companies the ability to generate massive volumes of content at low cost. Many of these sites blurred the line between UGC (User-Generated Content) and corporate content, giving an impression of authenticity while being engineered for search performance. As a result, curation media became a dominant force in Japanese SEO marketing during the 2010s.
What Was WELQ?
A major turning point came in December 2016. DeNA, a major Japanese tech company primarily known for games, launched a curation site called WELQ in 2015. It focused on medical and health-related content, publishing articles on topics ranging from common symptoms to serious conditions. The content was written by freelance contributors, many of whom lacked medical knowledge or credentials.
WELQ’s content ranked highly in Google search results due to aggressive SEO strategies. However, the quality and credibility of the articles were severely lacking. One notorious article, for example, claimed that shoulder pain might be caused by spiritual possession by animal spirits—a completely baseless and pseudoscientific assertion. The majority of articles had no expert supervision and often recycled inaccurate or misleading information.
The SEO Strategy Behind WELQ
WELQ’s SEO strategy was straightforward but problematic. Writers with no medical background created articles by stitching together content from other sites, often paraphrased or copied with minimal effort. These articles were stuffed with targeted SEO keywords and rapidly published in large quantities. The goal was to dominate search rankings for health-related queries.
By June 2016, WELQ was attracting nearly six million visitors per month. Many users encountered these articles through search engines, unaware of their questionable origins. While the content appeared authoritative, it often lacked any factual basis and, in many cases, was plagiarized.
Public Backlash and Media Exposure
In late 2016, criticism began to emerge on social media, especially from healthcare professionals who raised concerns about the spread of misinformation. In November, a whistleblower from within DeNA exposed internal manuals that instructed writers on how to rewrite content from other publishers, effectively encouraging copyright infringement.
This revelation shocked the public. People assumed that articles from a large company like DeNA were reviewed by experts. In reality, most of the medical articles were unsupervised and factually incorrect. In response, the Tokyo Metropolitan Government’s Bureau of Social Welfare and Public Health launched an investigation into possible violations of Japan’s pharmaceutical advertising laws.
DeNA attempted to regain trust by announcing that problematic articles would be removed and that future content would be reviewed by professionals. However, this announcement was met with widespread skepticism and criticism.
The WELQ Issue Covered by Major Japanese Newspapers
DeNA’s Response: Site Closures and Official Apology
Further investigation revealed that DeNA had used similar tactics across a total of 10 curation websites, covering topics such as travel, interior design, fashion, and more (including iemo, Find Travel, cuta, UpIn, CAFY, JOOY, GOIN, PUUL, and MERY).
Faced with mounting criticism from experts, media, and the public, DeNA decided to shut down all 10 platforms. The company held a public press conference in which its CEO issued a formal apology. An independent investigative committee, including third-party experts, was formed to analyze the incident and propose preventive measures.
The impact of the scandal was not limited to DeNA. Other companies using similar SEO-driven content strategies began to voluntarily take some of their pages offline to avoid becoming the next target of scrutiny.
The Long-Term Impact on Japanese SEO
The WELQ incident had a profound and lasting impact on the Japanese SEO industry. Many low-quality content sites were shut down, and it became clear that spreading false or misleading information could lead not only to ranking penalties but also to legal and reputational consequences—including full website closures.
In response, Google updated its algorithm for the Japanese market in February 2017, specifically targeting low-quality content. This marked a turning point in how content quality was evaluated. The concept of E-A-T (Expertise, Authoritativeness, and Trustworthiness)—which gained prominence globally in 2018—can trace its Japanese roots to this moment. Today, the standard has become even stricter, with E-E-A-T (adding “Experience”) shaping modern SEO practices in Japan and beyond.
The WELQ case shifted the industry focus from content volume to quality, a principle that continues to guide ethical SEO today.
Google’s Algorithm Update for the Japanese Market in 2017
What Global Marketers Must Understand About Japanese SEO in the Age of AI
The WELQ scandal offers vital lessons not only for Japan, but for marketers around the world—especially as we enter the era of AI-generated content. Search algorithms, even when sophisticated, are not perfect. Tactics that manipulate algorithms—such as content scraping, misinformation, or keyword-stuffing—may work temporarily, but they erode long-term trust.
In Japan, trust is paramount. If a site publishes content that is unreliable or misleading, it won’t just lose traffic—it risks being removed from the web altogether. With the growing use of AI to generate articles, there’s an increasing risk of publishing content that lacks human oversight or contains factual errors.
Even if such AI-generated pages achieve high rankings in the short term, they are unlikely to sustain their visibility in Japan. Worse still, operators may be forced to shut down the site entirely if public backlash or regulatory scrutiny follows.
For anyone engaged in SEO in Japan, it’s critical to understand that credibility, originality, and responsibility are non-negotiable. In the age of AI, quality is more important than ever.