Tsuria: Fishing Units & Log

"What is a #1.5 Japanese line in lb?" "How many grams is 3/8 oz?" "How tight should my drag be?" — Tsuria is a toolbox that answers the number questions of fishing, right at the water.

[Squid jig (egi)]
Egi size ↔ length (cm) ↔ weight. The size is in Japanese sun, so length is almost exactly size × 3 cm. Weight varies by maker, so it is shown as a range.

[Lead strip]
Weight from thickness × width × length — or the length you need for a target weight. It is computed from the density of lead rather than a lookup table, so every size is equally accurate.

■ What makes this different
・PE sizes from 0.1 to 30. What JAFS actually standardises for PE is denier (1 size = 200 denier) — the "standard diameter" you see in most charts is an agreed manufacturer figure, not the standard. This app makes that distinction explicit.
・Shaku and sun are defined units, so they are exact. Hiro and yabiki come from body proportions, so they are always shown as a range. Numbers that are fixed and numbers that are estimates are never mixed.

■ 10 tools inside

[Line converter]
Convert between Japanese line sizes (gou), pounds and diameter (mm). Nylon and fluorocarbon diameters follow the official JAFS standard table (Japan Fishing Tackle Makers Association). For PE, sizes are based on JAFS denier, and makers' nominal diameters are shown as a guide. This is the key to decoding Japanese-made lines (#0.8, #1.5 …). Strength is not standardized, so we show a realistic range across makers as a guide (always trust your line's label). Supports nylon, fluorocarbon, ester and PE braid.

[Sinker & lure weight]
Convert Japanese sinker sizes ↔ grams ↔ ounces. One Japanese sinker size unit = exactly 3.75 g. Understands fractions like 1/32 or 3/8 oz. Includes a split-shot quick table (G8–6B) with the real weight range across makers.

[Drag setting]
From your line's rated strength (lb/kg), calculates the widely used 1/4–1/3 rule of thumb for initial drag, in kg and g.

[Reel retrieve]
Gear ratio + spool diameter → cm per handle turn, and how many turns to bring in a given distance.

[Line capacity]
A spool rated "#3 × 150 m" — how many metres of #2 will it hold? Exact conversion by size ratio, or by diameter² across different materials (PE ↔ nylon).

[Leader balance]
A sensible leader range for your main line (from the same size down to 2 sizes thinner — the common rule).

[Depth & length]
Convert hiro (the Japanese fathom, 1.5 m) ↔ metres ↔ feet.

[My tackle]
Save up to 30 setups (rod, reel, line, leader). Each saved setup shows its drag estimate and retrieve at a glance, and can be shared via your device's share sheet.

[Catch log]
Log each catch with a photo, date, species, length, weight, spot and notes (up to 100), and link the tackle you used. As records grow, [Personal bests] per species build automatically.

[Share card]
Turn a catch into a beautiful single card image — photo, species, size and date — ready to share to social media or friends.

■ Highlights
• No sign-up needed — open the app and start converting right away
• The numbers you enter, your catch log and your photos are saved on your device; the app does not send them anywhere
• 8 languages
• Only a small top banner ad — no full-screen ads
• Watch one video and the top ad — space and all — is gone for 60 minutes. A one-time purchase removes it for good
• Only the ads go away: every converter, your catch log, photos and saved tackle stay free
• Dark mode

■ Please note
Line strength labels are maker conventions, not a standard; figures here are guides based on a range of makers — always trust the product label. Drag values follow the common 1/4–1/3 rule of thumb; knots and guide friction change your real margin, so verifying with a spring scale is recommended for big fish. Capacity and retrieve are geometric approximations.

Made by GRAMSHIFT, an independent developer in Japan — the home of gou sizes.