Verified claims registry
Every numbered fact we cite in guides and tools lives here with a verbatim source quote, verification date, and authority tier. Other writers can link back to a stable claim id instead of re-quoting manufacturer pages.
CI fails the build when any claim is older than 365 days; warnings start at 180 days. See methodology and source policy.
| Claim | Value | Source | Freshness |
|---|---|---|---|
BWF feathered shuttle feather count bwf-shuttle-feathers Tier 2: Standards body (BWF) | 16 feathers | BWF Laws of Badminton (Shuttle specification) Verified 2026-05-15 The shuttle shall have 16 feathers fixed in the base. | Fresh |
BWF feathered shuttle weight range bwf-shuttle-weight-g Tier 2: Standards body (BWF) | 4.74-5.50 g | BWF Laws of Badminton (Shuttle specification) Verified 2026-05-15 The shuttle shall weigh from 4.74 to 5.50 grams. | Fresh |
BWF net height at the centre bwf-net-height-centre-m Tier 2: Standards body (BWF) | 1.524 m | Verified 2026-05-15 1.524 m at the centre of the court | Fresh |
BWF net height at the posts bwf-net-height-posts-m Tier 2: Standards body (BWF) | 1.55 m | Verified 2026-05-15 The top of the net from the surface of the court shall be 1.524 m at the centre of the court and 1.55 m over the side lines for doubles. | Fresh |
BWF official court length bwf-court-length-m Tier 2: Standards body (BWF) | 13.4 m | Verified 2026-05-15 The court shall be a rectangle laid out with lines... the length of 13.40 m and a width of 6.10 m for doubles, 5.18 m for singles. | Fresh |
BWF official court width (doubles) bwf-court-width-doubles-m Tier 2: Standards body (BWF) | 6.10 m | Verified 2026-05-15 6.10 m for doubles | Fresh |
BWF official court width (singles) bwf-court-width-singles-m Tier 2: Standards body (BWF) | 5.18 m | Verified 2026-05-15 5.18 m for singles | Fresh |
BWF standard match format bwf-match-format Tier 2: Standards body (BWF) | best of 3 games to 21 | BWF Laws of Badminton (Scoring System) Verified 2026-05-15 A match shall consist of the best of 3 games... A game is won by the side that first scores 21 points (with 2 clear points lead from 20-20 and game won at 30 by single-point lead). | Fresh |
Industry convention: 3U racket weight band (unstrung) weight-class-3u-g Tier 4: Independent measurement or industry convention | 85-89 g | Yonex Astrox 99 Pro product page (representative 3U row) Verified 2026-05-09 3U (Avg. 88g) Note: Industry convention derived by sampling Yonex per-line product pages. Specific 3U averages range from ~85g to ~89g across SKUs; the band 85–89g is the consensus reading. No single Yonex page lists the band itself. | Fresh |
Industry convention: 4U racket weight band (unstrung) weight-class-4u-g Tier 4: Independent measurement or industry convention | 80-84 g | Yonex Astrox 99 Pro product page (representative 4U row) Verified 2026-05-09 4U (Avg. 83g) Note: Industry convention derived by sampling Yonex per-line product pages. Specific 4U averages range from ~80g to ~84g across SKUs; the band 80–84g is the consensus reading. | Fresh |
Industry convention: 5U racket weight band (unstrung) weight-class-5u-g Tier 4: Independent measurement or industry convention | 75-79 g | Yonex Nanoflare 700 Play product page (representative 5U row) Verified 2026-05-15 5U (Avg. 78g) Note: Industry convention derived by sampling Yonex per-line product pages. 5U entries publish averages around 75–79g. Verbatim text varies per SKU; this entry is a placeholder until a single Yonex grip & weight reference page is located. | Fresh |
Yonex Astrox 99 Pro 4U stringing advice yonex-astrox-99-pro-tension-4u-lb Tier 1: Manufacturer product page | 20-28 lb | Yonex ASTROX 99 PRO product page Verified 2026-05-09 Stringing Advice | 4U: 20 - 28 lbs | Fresh |
Yonex Astrox 99 Pro shaft flex yonex-astrox-99-pro-flex Tier 1: Manufacturer product page | Stiff | Yonex ASTROX 99 PRO product page Verified 2026-05-09 Flex | STIFF | Fresh |
Yonex grip G4 approximate circumference yonex-grip-g4-inches Tier 4: Independent measurement or industry convention | 3 5/8 in | Yonex grip-size ladder (industry convention) Verified 2026-05-15 G4 Note: Yonex publishes grip size codes (G2/G3/G4/G5/G6) per product page but does not publish a single grip-size dimension chart at a stable URL. Industry consensus measures G4 at approximately 3 5/8" circumference, with smaller numbers indicating thicker grips. This row stays at Tier 4 until a Yonex grip-dimension reference page is located. | Fresh |
Yonex grip G5 approximate circumference yonex-grip-g5-inches Tier 4: Independent measurement or industry convention | 3 1/2 in | Yonex grip-size ladder (industry convention) Verified 2026-05-15 G5 Note: Industry consensus places G5 at approximately 3 1/2" circumference. Same caveat as `yonex-grip-g4-inches`: Yonex does not publish a single dimension chart, so this is Tier 4 derived. | Fresh |
Yonex Nanoflare 1000 Z 4U stringing advice yonex-nanoflare-1000z-tension-4u-lb Tier 1: Manufacturer product page | 20-28 lb | Yonex NANOFLARE 1000 Z product page Verified 2026-05-09 Stringing Advice | 4U: 20 - 28 lbs 3U: 21 - 29 lbs | Fresh |
Yonex Nanoflare 1000 Z shaft flex yonex-nanoflare-1000z-flex Tier 1: Manufacturer product page | Extra Stiff | Yonex NANOFLARE 1000 Z product page Verified 2026-05-09 Flex | Extra Stiff | Fresh |
Machine-readable source: content/claims.json in the public repository.