Why the Association Is Publishing This Book

Sushi is now a world cuisine. You find sushi stalls not only in the cities of North America and Europe, but also in the markets and night markets of Asia, the Middle East, Latin America, and Africa. According to a survey by Japan's Ministry of Agriculture, Forestry and Fisheries, there are about 181,000 Japanese restaurants outside Japan (2025). The Association is proud of this spread.

At the same time, the Association is deeply concerned. What spread around the world was the "form" of sushi. The "conditions" that kept that form safe did not spread with it. At a street stall where the air is 35°C, raw fish sits on half-melted ice. Vinegared rice made in the morning is still being sold in the evening. Sushi made without knowledge of hygiene causes food poisoning. It can even lead to accidents that put lives at risk. The Association wants to stop this.

That is why the first pillar of this book is hygiene. It is no accident that sushi in Japan could be eaten raw. Four things work together: a low-temperature supply chain, a short time between shaping a piece and eating it, the acid and salt in the vinegared rice, and the chef's training. Only when all four come together is eating raw fish safe. If even one is missing, safety breaks down. And only a chef who knows "why we do it this way" can notice when it has broken down.

After hygiene, we put the most weight on the knowledge to handle ingredients correctly and the skill to make delicious sushi. How is aging different from spoilage? How should you arrange the inside of a refrigerator? Why can sushi be shaped with bare hands? We have written down the reasons behind the things chefs take for granted.

Chefs who make sushi outside Japan will also read this book. So we did not assume Japanese common knowledge. We wrote out the "why" as well.

Grade 2 and Grade 1: Why We Combined Them in One Book

The Japan Sushi Association's certification has four levels, from Grade 4 to Grade 1. Grade 4 and Grade 3 are the stages for learning the basics of sushi, and they have no written exam. Only Grade 2 and Grade 1 have a written exam.

Grade 2 is the first written grade that a chef with work experience takes. It asks two things: what you do in the kitchen, and why you do it. For example, it is not enough to know the procedure "Take out of the refrigerator only the fish you will use, and put it back right away." You must be able to give the reason in your own words: "While the fish is out, bacteria keep doubling, and putting it back in the refrigerator does not reduce them."

Grade 1 is the highest grade of the certification. Chefs who have passed Grade 2 take a practical exam at the exam site and a written exam. You must be able to explain the same topics one level deeper, in the language of science. For example, why are vinegar and salt not enough to kill Anisakis, and why is freezing necessary? You answer down to the basis for the numbers. In addition, Grade 1 covers the management needed to open a restaurant and keep it running.

Until now, there were two Official Textbooks, one for Grade 2 and one for Grade 1, and much of their content overlapped. So we combined them into one book. The exam scope and depth now differ by grade.

How to Read the Grade 1 Mark

In this book, material that is for Grade 1 only carries a small mark that says "Grade 1." The mark can appear on section headings, subheadings, boxes, tables, and review questions. If a section heading has the mark, the whole section is Grade 1 material. If a subheading has the mark, the material under it, up to the next subheading, is Grade 1 material. For boxes, tables, and review questions, only the ones with the mark are Grade 1 material. Part VIII, on running a sushi restaurant, has the mark on each chapter title, so each of those chapters is entirely Grade 1 material.

Here is what to study. If you are taking Grade 2, study the parts without the mark. If you are taking Grade 1, study the whole book. The parts without the mark are common to both Grade 2 and Grade 1.

If you are taking Grade 2, you are welcome to read the parts with the mark. Reading them will help you understand the Grade 2 material better.

How This Book Is Organized

This book has eight parts and five appendices (Table 0-1). It begins with food safety. It then moves on to shari (sushi rice), fish, neta (toppings), seasonings and condiments, techniques and tools, and history and the chef's mindset. The last part, Part VIII, covers running a sushi restaurant and is Grade 1 material only. Every reader should read Part I, on hygiene, first.

Every chapter follows the same pattern. It opens with an introduction and "In this chapter you will learn." Then comes the main text. It ends with a "Chapter summary" and review questions. Each review question asks you to choose one answer from five options, and each chapter has 3 questions. One of the 3 comes from Grade 1 material.

Types of Boxes

Throughout the main text, we have placed six kinds of boxed features. They are Sushi talk, Key points, The chef's craft, Outside Japan, Life-threatening, and The science behind it. Here is what each one looks like.

When a technical term appears for the first time, we mark it, like this: temperature danger zone. A simple explanation follows right after. For the temperature danger zone, that explanation is "the range of temperatures in which bacteria grow well." Terms are also collected in Appendix C at the back of the book.

Tips for Studying

First, learn each number as a set of three: the number, the condition, and the reason. For Anisakis, take the number "−20°C for 24 hours or more." Add the condition, "start counting after the center reaches −20°C." Then add the reason, "we freeze because vinegar and salt do not kill them." If you can state the reason, you will not be fooled by an option that swaps the conditions.

Second, each time you finish a section, try to state the "why" in one sentence. In the review questions, do not stop at choosing the right answer. Also try to explain why each of the other four is wrong.

Third, check things in your own restaurant. Take a thermometer and measure the temperature inside your refrigerator. Measure how many degrees fish on the cutting board reaches after how many minutes. This is the surest way to learn.

This book will also have an audiobook edition. So that it is easy to follow by ear, we have kept sentences short. We have also explained the contents of tables and figures in the main text.

To readers outside Japan: the numbers in this book are based on Japanese standards. Health authority rules differ by country, state, and city. Always check the rules where your restaurant is located. When they differ from the Japanese standards, follow whichever is stricter.

If you get results in your own restaurant that differ from this book, please let the Association know. This book is a textbook that will grow through repeated revisions.

The Written Exam and the Conventions of This Book

The written exam draws questions from the Association's question bank, in fixed proportions for each subject area. Grade 2 questions come from the parts without the Grade 1 mark. Grade 1 questions come from the whole book. The questions change each time you take the exam, so memorizing questions and answers will not work. Appendix E, "Exam scope and question guidelines," shows which areas questions come from and in what proportions.

Temperatures are given in degrees Celsius (°C). Food temperature is the temperature of the food itself. Core temperature is the temperature inside the thickest part of the food. Refrigerator air temperature is the temperature of the air inside a refrigerator or freezer. This book keeps these three apart. When we write "10°C or below," that includes 10°C. The exam names are written only as "Grade 2," "Grade 1," and "this certification exam."