#Japan #Chiyoda #Gaprise #LCP #TTFB

Overview of the Latest Web Performance Rankings

In June 2026, Gaprise, a digital business support company, released its latest ranking of EC site loading speeds in Japan, drawing attention to key findings and improvement examples among the top online retailers.

Survey Details

1. Research Period

The data collected reflects insights from June 2026.

2. Research Authority

Conducted by Gaprise, a prominent overseas SaaS trading firm headquartered in Chiyoda, Tokyo.

3. Target Subjects

The study analyzed websites of the top 300 online retailers as indicated by the 85th edition of the mail order sales rankings published by a well-known通販新聞社.

4. Data Collection Method

Using Google's official dataset from the Chrome User Experience Report, the study compared Largest Contentful Paint (LCP) across these websites evaluated under 4G connections on mobile devices. For more information on the dataset, refer to Google’s documentation.

Understanding LCP

LCP stands for Largest Contentful Paint and is one of the core web vitals defined by Google. It measures the time taken for the main part of the webpage (typically the largest image or the main heading text) to appear after the page has been opened. A lower LCP value indicates that key content is displayed more quickly, improving the user’s perception of loading speed. Google defines a good user experience when the LCP element appears within 2.5 seconds of the page's load start. If the LCP exceeds 4 seconds, the experience is considered poor. Notably, Renault has demonstrated that achieving an LCP of under 1 second can yield considerable benefits in performance.

LCP Improvement Case Studies

More details can be found in Renault's case studies available here.

Insights on Ranking (Top 10)

The rankings reveal that there are 115 sites outperforming major EC players like Amazon (Rank 116, LCP 1.459 seconds), Yodobashi.com (Rank 129, LCP 1.502 seconds), and Bic Camera (Rank 101, LCP 1.391 seconds). This indicates rising consumer expectations regarding display speed, signifying that merely matching industry leaders is no longer sufficient for differentiation.

What Causes the 5.8x Performance Gap?

The key differentiator between leading and lagging websites is not merely front-end optimization but the server response time (Time to First Byte, TTFB). Websites that achieve an LCP of less than 1 second uniformly maintain a TTFB of less than 0.5 seconds.

Many companies focus extensively on front-end improvements such as image compression and JavaScript lazy loading. However, recent data shows that without addressing TTFB, no level of front-end refinement can exceed the '1-second barrier’. Websites with an LCP of under 1 second typically undergo comprehensive backend infrastructure evaluations.

For insights on TTFB optimization and CDN usage, additional resources like “Top 10 Global CDN in 2026” provide extensive details.

Additional Resources

The complete data set, which includes rankings up to 444, a scatter plot of LCP vs. TTFB among the 300 companies, and an analysis of characteristics of websites with significant improvement potential, can be found on our media platform, MarTechLab.

Free Website Performance Diagnosis

Currently, Gaprise offers a free diagnostic service for website performance. This includes an assessment of overall speed along with specific metrics such as Time to First Byte (TTFB) and Largest Contentful Paint (LCP). Interested parties can apply for this free diagnosis here.

About Gaprise

Founded in January 2005, Gaprise acts as a 'SaaS trading company', discovering advanced overseas technologies and facilitating their introduction and utilization in the Japanese market. Through alliances with globally recognized tech firms, we've supported business growth across various aspects ranging from digital marketing to AI utilization.

With an anticipated growth in Japan's enterprise IT market expected to reach 30 trillion yen, the SaaS sector is projected to expand further. Gaprise aims to continue acting as a bridge connecting advanced technologies to Japanese enterprises, fostering the creation of new value.