Preparing eel (unagi) is one of the most demanding tasks in Japanese cuisine. Slippery skin, firm bones, and a unique preparation method require a knife unlike any other. That is where the Eel Knife—also known as Unagi-saki or Osaka-saki—comes in: a blade designed exclusively for opening, splitting, and preparing eel with speed and precision.

Unlike most Japanese knives, the Eel Knife is not primarily a slicing tool. Its role is to pierce, open, and separate the eel along the backbone while controlling the tough skin and fine bones. Depending on the region and cooking style, different shapes evolved, but all share one purpose: to make a difficult, slippery fish manageable and efficient to process.

The most distinctive feature of the Osaka-style Eel Knife is its short, sturdy blade and sharp, pointed tip. This tip is used to stab into the eel’s head or body and anchor it to the cutting board, a crucial step in traditional preparation. The relatively thick spine and compact shape provide strength, control, and safety during a process that demands both force and finesse.

While sashimi knives pursue elegance and long, flowing cuts, the Eel Knife is a purely functional tool. Its design prioritizes control, leverage, and durability over visual refinement. In this sense, it represents another side of Japanese craftsmanship: tools that are shaped not by appearance, but by the exact demands of the job.

Behind every perfectly grilled kabayaki eel is this humble, specialized knife. Rarely seen by diners, the Eel Knife is an indispensable backstage tool that supports one of Japan’s most beloved and technically challenging dishes. It is a reminder that Japanese knife culture is not only about beauty and sharpness—but also about respecting the ingredient and mastering the process.

What makes the Eel Knife even more fascinating is that its shape changes from region to region, reflecting how each area prepares and thinks about eel.

In Kanto (Tokyo), chefs use the Edo-zaki, a knife with a sharply angled tip, designed to open the eel from the back. Its short handle and compact form make it feel almost like holding a brush, allowing extremely precise, controlled movements in tight spaces.

In Kansai (Osaka), the tradition is different. Here, the Osaka-zaki is used—a heavier, more robust knife with the steel extending deep into the handle. This design suits the Kansai method of splitting the eel from the belly, and prioritizes strength, stability, and decisive action.

In the Nagoya and Ise regions, you find the Nagoya-zaki, with its distinctive rounded rectangular shape. It is designed to avoid damaging the internal organs, and can be seen as a quiet fusion of Kanto and Kansai philosophies—a reflection of the region’s role as a cultural crossroads.

Kyoto, meanwhile, uses a form that resembles a small Chinese cleaver, versatile enough to handle eel and other fish alike—an expression of the city’s refined but practical culinary culture.

These differences are not accidents of design. They are the physical record of regional history, cooking methods, and values.
The Eel Knife shows us that in Japan, even when working with the same ingredient, tools evolve to match local wisdom—and that is what gives Japanese knife culture its extraordinary depth.