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https://ndl.go.jp

SEO

· 7 checks — Canonical, meta, content depth, internal links, image SEO, and hreflang rolled into one auditable list.
SCORE
78
GRADE
C
FIX
1
REVIEW
2
PASS
3
INFO
1

Cross-tab audit — SEO, performance, crawlability, mobile, structured data

Checks
7
3 PASS 2 REVIEW 1 FIX
F
Content Depth
Action
285 words, Very Easy
FIX
285 words, Very Easy
Warning::
Page has 285 words — thin content
Most well-ranking pages have 300+ words of substantive content.
Info::
Text-to-HTML ratio is 3%
Very low ratio suggests heavy framework overhead or boilerplate.
Info::
Reading level: Very Easy (grade 7)
Warning::
Thin content — only 285 words
Got: 285 words
285 words

Thin content

Reading level

Very Easy
Easy
Fairly Easy
Standard
Fairly Difficult
Difficult
Very Difficult

Grade 7

Text-to-HTML Ratio

3% text 97% HTML

8 KB / 285 KB

Most well-ranking pages have 300+ words of substantive content.

Why this matters

Thin content (<300 words) rarely ranks — Google quality guidelines explicitly call out thin pages.

Source: Google Search Quality Guidelines

Very low ratio suggests heavy framework overhead or boilerplate.

Why this matters

Informational: ratio of visible text bytes to total HTML bytes. Very low ratios suggest excessive markup overhead.

B
Canonical URL
Minor issues
REVIEW
Minor issues
Warning::
No canonical tag found
Search engines will determine the canonical URL themselves, which may cause duplicate content issues.
No Canonical URL Set
Page URL https://ndl.go.jp Canonical (not set)

Search engines will determine the canonical URL themselves, which may cause duplicate content issues.

Why this matters

Without a canonical, Google may treat each URL variant (with/without slash, with tracking params, http/https) as duplicate content and split ranking.

Learn more ▾

A canonical link tells Google which URL is the 'real' one when multiple URLs serve identical content. Without it, link equity gets split across variants and none of them rank as well as a single canonical version would. One <link rel="canonical"> tag in <head> covers it.

Source: Google Search Central

B
Schema Markup Audit
3 schema types detected
REVIEW

Rich result eligibility

BreadcrumbList Eligible

Breadcrumb trail

WebSite Eligible

Sitelinks search box

Article Not eligible

Article rich results

Missing: image, author

Detected schema types

BreadcrumbList json-ld → Breadcrumb trail
1/1 required
Required fields (Google)
  • itemListElement — Required — the breadcrumb chain renders nothing without this
Google's spec for this type
WebSite json-ld → Sitelinks search box
2/2 required · 1/1 recommended
Required fields (Google)
  • name — Required for the sitelinks search box
  • url — Required to anchor the search box to your domain
Recommended fields
  • potentialAction — Enables the in-SERP search box
Google's spec for this type
Article json-ld → Article rich results
2/4 required · 0/2 recommended
Required fields (Google)
  • headline — Required — used as the rich result title
  • image — Add at least one high-resolution image (1200px+ wide) Required for top-stories carousel eligibility
  • author — Add an author Person or Organization with name Required by Google's E-E-A-T guidelines
  • datePublished — Required for time-sensitive rich results
Recommended fields
  • dateModified — Add dateModified when the article is edited Signals freshness to the news algorithm
  • description — Add a description / dek string Used as the result snippet
Google's spec for this type

Your Article structured data is missing required fields for Google's Article rich results. Without these, the page won't qualify for rich results.

Why this matters

Schema entity missing required properties — Google's rich-result eligibility check fails; the schema is in source but never renders enhanced.

Source: Google Search Central

A
Meta Tags
Title: 21 chars
PASS
Title: 21 chars
Info::
Page title is set
Got: 国立国会図書館
Warning::
Title is only 21 characters — consider expanding
Info::
Title and H1 have very different wording
Alignment helps users confirm they've reached the right page.
Title

"国立国会図書館"

21 characters Too short
Title: 国立国会図書館
H1: 国立国会図書館
Match: Very different
Robots: Indexable (no restrictions)

Alignment helps users confirm they've reached the right page.

Why this matters

Title and H1 disagree significantly — Google may treat one as the canonical topic and the other as off-topic, weakening ranking.

Learn more ▾

Title is the SERP headline; H1 is the on-page headline. They should describe the same page. Large divergence (different topics, different keywords) signals confusion and Google may rewrite the title in SERP. Align both to the same primary topic.

Source: Google Search Central / on-page SEO

A+
Image SEO
9 images, 8 descriptive filenames
PASS
9 images, 8 descriptive filenames
Info::
1 image(s) have hash/generic filenames
8 descriptive
0 hash-based
1 generic
9 total
FilenameQualityAltIssues
x.pnggeneric✓1
Current: x.png
Suggested: brand.png

See Accessibility tab for detailed alt text quality analysis.

Hreflang
0 hreflang tags
INFO
0 hreflang tags

No hreflang tags detected.

Hreflang tags are only needed for multilingual or multi-regional sites.

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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