ものとする

ものとする is a formal expression used primarily in legal documents, contracts, regulations, and official guidelines. It has two main usages:

1. "Shall" – Stipulating rules or obligations

In legal and regulatory contexts, ものとする functions like the English "shall" or "is to be," establishing what must be done or what is expected. This is by far its most common usage and appears extensively in contracts, company rules, and laws.

In this usage, ものとする carries an authoritative tone – it is not a suggestion but a formal declaration of how things are to be done. It is softer than なければならない (must) but still conveys a binding obligation or standard procedure.

2. "To assume / to consider as" – Treating something as a given

ものとする can also mean "to assume that" or "to treat as," establishing a premise or hypothetical condition for the purpose of discussion, calculation, or planning.

Here, something is treated as though it were true or established, even if it may not literally be the case. This usage appears in academic problems, official notices, and formal hypothetical statements.

Related forms

• ものとみなす – a stronger variant meaning "shall be deemed as," used in legal texts to treat something as an established fact.
• こととする – similar in function but slightly less formal; also used in official contexts to mean "it is decided that" or "shall."
• The past form ものとした can appear in narrative contexts or when referring to assumptions that were established previously.