On the Tsumoto Method: Technique, Risk, and the Overlooked Prerequisites

In recent years, the Tsumoto method has gotten a lot of attention in fishing and cooking circles.

It has a clear process, visual steps, and it’s easy to film, replicate, and talk about.

These qualities make it an extremely appealing way to handle fish.

I get why it’s popular.

For most people, dealing with blood, fishy smells, and the uncertain risks of poor handling is already unsettling.

The Tsumoto method offers a process that looks clean, complete, and gives you a definitive answer — and that’s genuinely convincing on a psychological level.

But after hands-on practice and long-term observation, I think there are still some commonly overlooked prerequisites behind this technique.

Invasive processing doesn’t mean lower risk

The Tsumoto method requires tools and water to be introduced inside the fish body. By nature, it’s an invasive process.

Under ideal conditions — where all tools, water sources, and procedures are kept highly sanitary — it can reduce some issues caused by residual blood.

But from a risk management perspective, invasive procedures also introduce new variables.

The fish’s interior, originally a relatively closed and near-sterile environment, now depends entirely on external conditions to stay stable.

This means that if any single step goes wrong, the risk can actually be amplified.

This isn’t about whether the technique is right or wrong — it’s about the structural difference in how the process works.

A common misconception about “delaying rigor mortis”

One frequently cited benefit of the Tsumoto method is that it delays rigor mortis.

But in practice, this effect is often overstated.

Whether a fish enters rigor mortis depends mainly on the stress it endured during capture, whether bleeding was done properly, and subsequent temperature control.

Whether the blood has been thoroughly flushed out is not a primary factor.

When bleeding is done correctly and the fish is cooled down quickly, the Tsumoto method’s contribution to delaying the onset of rigor mortis is actually quite limited — the marginal benefit just isn’t that significant.

What I actually use: ice killing

Rather than using invasive procedures to alter the fish’s internal state, I prefer to use temperature and time to guide the fish through the process it would naturally go through anyway.

My go-to method is ice killing.

After catching the fish, I immediately bleed it behind the gills, then place it directly into saltwater ice to bring the temperature down.

The point of this isn’t to delay rigor mortis.

It’s to let the fish lose consciousness quickly through a sharp temperature shock, avoiding the stress buildup from prolonged struggling.

The muscle tension caused by the cold actually helps push blood out more effectively.

Ice killing doesn’t delay the onset of rigor mortis, but it noticeably extends the duration of the rigor phase itself.

This keeps the fish in a structurally stable state for longer.

For aging and further processing, this actually gives you better control and safety.

Why ice killing isn’t trendy — but never stopped being used

Ice killing isn’t some new or cutting-edge technique.

In fact, it’s a method that professional fishermen have been using for a long time.

Because its purpose has never been about showing off — just efficiency and consistency — it doesn’t exactly catch your eye.

No special tools, no complicated process, and definitely no sense of ceremony.

Maybe that’s exactly why ice killing struggles to become a social media topic.

It can’t be packaged into a story that wows people.

But for those who work with fish day in and day out, a method that doesn’t need to be explained is precisely why it’s still in use today.

Technique should always come back to context

The Tsumoto method isn’t a wrong technique — it can work well under the right conditions.

But when a technique gets treated as the default answer, and people stop considering differences in environment, purpose, and risk structure, that’s usually where problems start.

For me, the key to choosing a fish handling method isn’t about whether it’s popular.

It’s about whether it can be reliably replicated under real-world conditions, and whether it leaves enough room for flavor development and aging down the line.

Some methods have stuck around for a long time — not because they’re romantic, but because they don’t go wrong.

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