Cuttlefish form large schools during their spawning period in May–June, and reach an autumn peak in September–November.

Particularly in June, water temperatures are stable at 12–24 °C on both the West Sea and South Sea, a time when cuttlefish are highly active.

According to water temperature and depth data from the Korea Maritime Institute (KMI), the central West Sea records an average temperature of 18–22 °C at depths of 60–120 m, while the southern South Sea records 20–24 °C at 70–110 m.

These conditions provide the optimal efficiency for Omorig rigs.

01Omorig rig principle and sinker selection

Omorig is a compound of ‘omori (weight) + rig (tackle)’, with the sinker and jig placed separately.

Heavy sinkers (15·20·25·30 go) → sink first and quickly reach the target depth, and a jig attached to a 1–1.5 m leader drifts with the current.

A 20 go sinker weighs about 75 g, 25 go about 90 g, 30 go about 110 g, and is chosen according to depth and current strength.

The deeper and stronger the current, the more you use a 30 go; in shallow, calm water, 15–20 go is used.

Slim long‑type sinkers minimize bottom snagging and allow rapid bottom‑layer exploration.

Sinker sizes
15·20·25·30 go
Sinker weight
75~110g
Jig size
2.5–4.0 go (South Sea) / 3.0–4.5 go (Jeju)
Main line
PE 0.6–1.2 go
Leader
Fluorocarbon 12–20 lb
Leader length
1~1.5m

02Rig adjustment for depth, temperature, and current

Cuttlefish move actively within a 12–24 °C temperature range.

In the central West Sea, the 60–120 m layer yields the highest catches, and deeper water brings stronger currents.

Therefore, for depths shallower than 80 m, 20–25 go sinkers are recommended; for depths over 100 m, use 30 go.

Jig colour varies with current and depth.

In shallow water and weak currents, natural‑coloured (transparent or silver) jigs reduce wariness, while in deep water, strong currents, or night time, glow jigs increase visibility.

The main line uses PE 0.6–1.2 go to balance strength and transparency, and a fluorocarbon leader of 12–20 lb provides bite transmission.

Central West Sea
Cheongpodae
70–110m
May–June
Southern South Sea
Near Geoje Island
80–120m
May–June
Southwest Jeju
Around Udo
90–130m
May–June

03Bite characteristics and safety points

Because the jig is attached to the end of the leader, a slight twitch is not detected.

Instead, a strong bite is felt when the jig fully hooks the hook, producing a pulling sensation.

The feel is judged by the resistance at the moment the hook is drawn into the water.

When the bite feels strong, immediately raise the lip to lift the hook.

Safety points: the jig hook is sharp and poses a high injury risk, so wear gloves and use a hook case when changing hooks.

Also, in strong currents the sinker may not stay on the bottom; add weight or switch to a slim long‑type sinker to minimize bottom snagging.

⚠ Common mistakes
  1. Undersizing the sinker weight causes the rig not to reach depth, leaving the jig near the surface.
  2. Using only dark‑coloured jigs in strong currents reduces visibility.
  3. If you miss the bite and do not raise the lip immediately, the jig disappears into the water.
⏱ Golden time
Sunset ± 2 h
Current weakens and temperature stabilizes, prompting active jig bites.
Early morning 03–05 h
As depth increases, cuttlefish rise to the surface and begin feeding.
Midday 10–12 h
Rising temperature drives cuttlefish down to the bottom, reducing bites.

04 FAQ