Hazmat Handler Class B (Otsu)

Particles and Waves

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About this app

Japanese-language practice for Japan's Class B Hazardous Materials Handler (Otsu) exam, covering categories 1 to 6.

The interface, questions and explanations are in Japanese. Japanese reading ability is required.

470 active original question records across six categories. Standard study for one selected category has 281 to 314 questions: 130 law questions, 128 physics/chemistry questions, and 23 to 56 questions about that category's properties, prevention and extinguishing. Category 4 has 314 questions, or 56 category-specific questions in exempt-subject mode.

This revision adds 195 original questions and removes 512 repetitive/template records from new practice while preserving their IDs and existing history. Progress indicators use the current active catalogue. Every choice has an explanation and supporting sources can be opened from the question.

Practice is distributed across the app's covered topics. Standard full mocks use 35 questions (15 law, 10 physics/chemistry, 10 properties), and half mocks use 17. For holders eligible for subject exemption, the property-only full mock has 10 questions and the half mock has 5. Mocks follow the examination format; they do not predict actual exam questions or guarantee a pass.

Free access: 10 drill answers in total, one half mock, and an initial three-day passive review trial. Mock answers do not consume the 10-answer drill allowance, and it does not reset daily. One non-consumable Pro purchase unlocks continued drills, full mocks, weakness review, unseen-only practice and continued passive review for all six categories. Restore Purchases is supported. There is no subscription or advertising.

The questions are bundled for offline practice. Study history is stored on the device. Network connections support store purchases and validation, question corrections, anonymous usage analytics and opening external sources. No account or advertising identifier is required. Share the app's public store link from the home screen without sending study records.

This is a supplementary question collection for basic and major topics. Its question count is not proof of exhaustive exam coverage. Check the official scope and combine it with a systematic textbook. Questions are independently written from laws and primary references; published examination questions and commercial textbook questions are not reproduced. There is no claim of external expert supervision or measured pass rate.

Official examination information: https://www.shoubo-shiken.or.jp/kikenbutsu/annai/subject.html
Fire Service Act: https://laws.e-gov.go.jp/law/323AC1000000186
Cabinet Order: https://laws.e-gov.go.jp/law/334CO0000000306
Ministerial Ordinance: https://laws.e-gov.go.jp/law/334M50000002055
Chemical references: https://chemicalsafety.ilo.org/

Particles and Waves makes this unofficial app and does not represent the examining body or any government agency. Laws and source references were checked on 2026-10-13. Confirm current eligibility, dates and application procedures with the examining body.

What’s new

Added 195 original questions across all six categories. Retired repetitive templates from new practice, preserved history, and clarified active counts, sources and scope.