This pattern has been test crocheted.

Seigaiha Virus C2C Blanket is a customizable, corner-to-corner (bias) blanket combining the traditional Japanese wave motif (Seigaiha) with the rhythmic beauty of the classic virus crochet stitch pattern.

Features

• Construction: Worked on the bias from corner to corner (C2C style) seamlessly in one piece, finished with a neat edging.
• Stress-Free Start: No long foundation chain to count and no complicated ratio calculations beforehand—simply crochet until you reach your desired short-side width!
• Versatile Geometry: Effortlessly customizable into either a Square or a Rectangle by choosing when to transition between the increase, straight, and decrease sections.
• Scale Freedom: Fully adaptable from small table accents (placemats, basket covers) to cozy lap throws, baby blankets, or large bedspreads.
• Stitch Pattern: A meditative combination of arches and open fan stitches that creates an elegant drape and highlights solid, tonal, or gradient yarns beautifully.

Size & Measurements

The pattern is fully customizable. Details for 3 finished sample sizes:

• Basket Cover (Square): Approx. 33.5 cm × 33.5 cm / 13.2” × 13.2”
• Baby Blanket (Square): Approx. 81.5 cm × 81.5 cm / 32” × 32”
• Gradient Lap Throw (Rectangle): Approx. 71.5 cm × 103 cm / 28.1” × 40.5” (Measurements taken after light blocking. Sizing is completely adjustable to your preferred dimensions.)

Yarn & Materials

• Yarn Used: Fingering weight yarn / Sock yarn (Sample shown in ATELIER mati Natural Dyed Superwash Sock Yarn, 85% Extra Fine Merino, 15% Nylon; approx. 400 m / 437 yds per 100 g skein)
• Estimated Yardage by Sample:
  • Basket Cover: Approx. 224 m / 245 yds (56 g total — 46 g main body + 10 g border)
  • Baby Blanket: Approx. 1,212 m / 1,325 yds (303 g total — 273 g main body + 30 g border)
  • Gradient Lap Throw: Approx. 1,320 m / 1,444 yds (330 g total across 4 gradient colors A–D)
• Hook: JP 5/0 (3.0 mm) / US D-3 or E-4, or size needed to obtain desired fabric and drape
• Gauge: 28 sts and 8 rows = 10 cm / 4” in pattern stitch after blocking. (Gauge is not critical for this project, but differences in gauge and yarn weight will affect finished measurements and yarn requirements.)

What’s Included

Your download includes 3 PDF files:
1. Main Pattern PDF (English):

• Complete step-by-step written instructions (US terms) for both square and rectangular formats.
• Standard right-handed crochet charts, construction diagrams, and Yarn Management Guide.

1. Main Pattern PDF (Japanese):

   • 日本語版パターン（標準の右利き用編み図、サイズ図、糸量ガイド）。

2. Supplementary Left-Handed Charts PDF:

   • Horizontally mirrored stitch charts only (Square & Rectangle).
   • Note: This file contains charts only and does not include written instructions, materials, or pattern notes. It is intended to be used alongside the Main Pattern PDF as a visual aid for left-handed crocheters.

Ideal for crocheters who enjoy the visual precision of Japanese charts paired with clear English written direction!

Special Thanks to My Testers

A heartfelt thank you to all the wonderful testers in Japan and overseas who helped bring this pattern to life!

They have created beautiful projects in various shapes (both square and rectangular), sizes, and color combinations. Be sure to check out the Projects tab to see their lovely work and find inspiration for your own blanket!

日本の編み図をご希望の方へ

本パターンをご購入いただくと、日本語版のパターンPDFもダウンロードしていただけます。

• 右利きの方：
  [Japanese] SeigaihaVirusC2CBlanket.pdf をダウンロードしてください。（日本国内で販売されている編み図と同じ内容です）
• 左利きの方：
  上記日本語PDFに加え、[Optional] LeftHandMirroredCharts.pdf（反転編み図のみを収録した補助ファイル）を併せてご利用ください。

※日本のショップ（STORES / BASE）では左利き用の反転編み図は付属しておりません。左利き用編み図をご希望の方はこちら（Ravelry）からご利用ください。