From Otsu-4 to all six Otsu classes
Hazardous Materials, Otsu (incl. Otsu-4)
Practice only what your selected class requires.
Covers Otsu classes 1–6, combining shared knowledge with class-specific questions for standard and exempted exam formats.
Classes 1–6280 questions per selected classStandard and exempted mocks
680 questions total
Before you start
- iOS app
- 危険物乙4・乙種全類 一問一答問題集
- What it does
- Practice for Japan's Hazardous Materials Otsu exam with explanations and subject-level feedback.
- Content and features
- All 6 Otsu classes, 280 questions per class / 17- and 35-question mock exams / Explanations for every answer choice
- Requirements
- iOS 16.0 or later
- Free access and purchases
- A limited free trial is available. A one-time in-app purchase unlocks further questions and mock exams; see the app for current limits and price.
- Before choosing
- Japanese-language exam practice. Independent of the exam authority, with no pass guarantee. Check current official rules and eligibility.
iOS facts checked: · Current App Store listing and purchase terms ↗
3-MINUTE CHECK
Try three questions.
Can you recall the reason?
The mini diagnostic is in Japanese, with a short explanation after each answer. No sign-up is required.
QUESTION 1 / 3
第4類（引火性液体）の性質として、消防庁の概要と一致するものはどれか。
CONTINUE IN THE APP
Continue in a study environment built for this exam.
Move from focused repetition to exam-format mock tests while keeping your study history.
This page and app are independent study aids, not official exam-authority products. Check current official information before taking an exam.