〜をもって

Formality Level: Formal / Written — official announcements, legal documents, ceremonial speech, formal notices

Classical/Literary Origin: をもって derives from classical Japanese をもちて, the te-form of もつ ("to have, to hold") preceded by the object marker を. In classical texts it expressed the means or instrument by which an action is performed: "holding X, by means of X." The modern form をもって has become a fixed formal expression used in two distinct senses: instrumental ("by means of") and temporal ("as of / with this ~, ending at ~"). Both are strongly associated with written, official contexts.

Structure

Form	Meaning	Example
Noun + をもって	By means of / with	実力をもって証明する
[Time noun] + をもって	As of ~, with this	本日をもって閉店いたします
これをもって	With this (set phrase)	これをもって式典を終了いたします

Note: をもちまして is a more polite/humble variant frequently heard in ceremonial announcements (closing ceremonies, meetings, speeches).

Meaning

Sense 1 — Instrumental: "By means of ~," "with ~," "using ~" Expresses the method, instrument, or quality with which an action is performed. It elevates the sentence register above the plain で particle. The noun before をもって is often abstract: 実力 (ability), 誠意 (sincerity), 努力 (effort), 全力 (full effort).

Sense 2 — Temporal limit: "As of ~," "with this ~" Marks a point in time at which something ends or a new state begins. Extremely common in formal closings of ceremonies, meetings, and official notifications of termination or commencement.

These two senses are both present in formal Japanese and must be distinguished from context. The temporal sense almost always involves a time noun (本日, 今月末, この公演) while the instrumental sense involves method/quality nouns.

Example Sentences

Instrumental — by means of

Japanese	English
彼は圧倒的な実力をもって、全国大会を制した。	He won the national championship by means of overwhelming ability.
誠意をもって交渉に臨んでいただきたい。	We ask that you approach the negotiations with sincerity.
その事実は客観的なデータをもって証明される。	That fact is proven by means of objective data.

Temporal — as of / with this

Japanese	English
本日をもって、このサービスは終了いたします。	As of today, this service will terminate.
今月末をもって、当社との契約は満了となります。	As of the end of this month, the contract with our company will expire.
これをもちまして、本日の式典を終了いたします。	With this, we conclude today's ceremony.

Common Mistakes

Replacing で with をもって in casual contexts: をもって sounds extremely stiff in conversation. ❌ 努力をもって頑張ります (in casual speech) sounds unnatural. Reserve it for formal writing and official speech.
Confusing the two senses: 本日をもって is always temporal, not instrumental. Ensure the noun type is appropriate for the intended reading.
をもって vs をもとに: をもとに means "based on ~" (〜をもとに計画を立てる = plan based on ~). These are not interchangeable; をもって does not mean "based on."

Compare With

Pattern	Register	Meaning	Key Difference
〜をもって (instrumental)	Formal	By means of ~	Elevated formal equivalent of で
〜で	All registers	By / with / at	Neutral instrument/means; not formal enough for official documents
〜によって	Formal/Semi-formal	By means of / due to	Broader causal/agentive use; less ceremonial than をもって
〜をもとに	Formal	Based on ~	Source material, not instrument or time limit
〜をもって (temporal)	Formal	As of ~, with this	Set a terminal or initial time boundary officially