～に基づいて

The Japanese grammar structure ～に基づいて (ni motozuite) is a formal and highly useful expression that translates to 'based on,' 'founded upon,' or 'in accordance with.' It is fundamentally derived from the noun 基 (moto), meaning 'foundation' or 'basis,' and the verb 付く (tsuku), meaning 'to attach' or 'to be set.' When combined into the te-form 基づいて, it indicates that the preceding noun serves as the fundamental basis, standard, or foundation for the action or state that follows. This structure is essential for learners aiming for CEFR B1 and above, as it elevates one's ability to explain the reasoning, origins, or rules behind specific actions, decisions, or creations.

Literal Breakdown

Noun + に (particle indicating target/location) + 基づいて (te-form of 基づく, to be based on).

Understanding the core concept of this grammar point requires recognizing that it implies a strong, often immovable foundation. It is not used for casual, fleeting reasons, but rather for solid frameworks such as laws, data, historical facts, survey results, or established rules. For instance, when a movie is based on a true story, the true story is the unchangeable foundation upon which the creative work is built. This nuance of a 'solid foundation' is what distinguishes it from other similar expressions.

When using this expression, the noun that comes before に基づいて is typically something objective and authoritative. You will frequently encounter words like 法律 (law), データ (data), 調査 (survey/research), 経験 (experience), and 計画 (plan) preceding it. The action that follows is usually a human action involving creation, judgment, evaluation, or execution. It shows that the action was not taken arbitrarily, but with a clear, justifiable rationale.

Core Nuance

Implies objectivity, authority, and a logical progression from a foundational concept to a resulting action.

Furthermore, the expression can be modified to directly connect two nouns. Instead of using the te-form に基づいて to connect to a verb, you can use the dictionary form に基づく to connect to another noun. For example, 法律に基づく決定 (a decision based on the law). This noun-modification form is extremely common in written Japanese, academic papers, and official documents, making it a crucial pattern to master for reading comprehension at the B2 and C1 levels.

In formal writing, you might also see the masu-stem form に基づき used instead of に基づいて. This serves the exact same grammatical function (connecting clauses) but carries a stiffer, more formal tone appropriate for legal texts, business reports, and news broadcasts. For example, 規則に基づき、処分を下す (to hand down a punishment based on the rules). Recognizing these variations ensures you are fully prepared to encounter this grammar in any context.

Formality Levels

に基づいて (Standard formal) vs. に基づき (Highly formal/Written).

To truly master this expression, one must practice identifying the 'foundation' in any given scenario. Whether it is a scientific theory forming the basis of an experiment, or a customer's feedback forming the basis of product improvement, the logical relationship remains the same. The foundation dictates the direction and nature of the subsequent action, ensuring consistency and reliability.

Using ～に基づいて correctly requires a solid understanding of its grammatical rules and the types of vocabulary it naturally pairs with. The fundamental rule is straightforward: it always attaches directly to a noun. There are no complex conjugations required for the preceding word. The structure is simply [Noun] + に基づいて + [Verb Phrase]. This simplicity makes it highly accessible for B1 learners, provided they understand the semantic restrictions of the noun being used.

Basic Structure

Noun + に基づいて + Action/State

Let us explore the most common categories of nouns that precede this grammar point. The first category includes rules, laws, and agreements. Words like 法律 (law), 規則 (rule), 条約 (treaty), 契約 (contract), and 方針 (policy) are perfect candidates. When these words are used, the sentence implies that the subsequent action is legally or officially justified. It shows compliance and adherence to an established standard.

The second major category involves information, facts, and evidence. Words such as データ (data), 事実 (fact), 調査結果 (survey results), 証拠 (evidence), and 統計 (statistics) are frequently used. In these cases, the grammar point highlights the objectivity and reliability of the action. It is often used in academic, scientific, or business contexts to prove that a decision or conclusion was not made randomly, but was derived from concrete information.

Noun Modification

Noun A + に基づく + Noun B

As mentioned in the previous section, the noun-modifying form ～に基づく is just as important as the te-form. When you want to describe a noun rather than an action, you must use に基づく. For example, instead of saying 'We evaluate based on performance' (業績に基づいて評価する), you might want to talk about a 'performance-based evaluation system' (業績に基づく評価システム). This structural shift is crucial for writing natural, sophisticated Japanese sentences.

A third category of nouns includes personal or collective experiences and philosophies. Words like 経験 (experience), 理念 (philosophy), 思想 (thought/ideology), and 信念 (belief) can be used. While these might seem slightly more subjective than laws or data, they still represent a solid, established foundation for the individual or organization taking the action. For instance, a company might operate 'based on its founding philosophy' (創業理念に基づいて).

Formal Written Form

Noun + に基づき、...

It is also important to note what CANNOT be used with this grammar point. You cannot use words that represent temporary states, minor personal whims, or physical materials in a literal sense. For example, you cannot say 'based on wood, I made a table' (木に基づいて机を作った). For physical materials, you would use で or から. You also wouldn't say 'based on my current mood' (今の気分に基づいて); instead, you might use で or によって. The foundation must be abstract, established, and authoritative.

The expression ～に基づいて is ubiquitous in Japanese society, particularly in environments that value formality, objectivity, and structured processes. While you might not hear it in casual banter between friends at an izakaya, it is a staple of professional, academic, and official communication. Understanding where and how it is used will significantly improve your listening comprehension and contextual awareness when navigating Japanese media and professional settings.

News and Journalism

Frequently used by news anchors to explain the rationale behind government actions or corporate decisions.

One of the most common places you will hear this expression is on the daily news (ニュース). News anchors and reporters use it to describe the basis of new policies, police investigations, and economic forecasts. For example, a reporter might state that the government is implementing a new health policy 'based on the advice of experts' (専門家の意見に基づいて). In this context, the phrase lends credibility and authority to the report, indicating that the actions being discussed are grounded in reliable sources.

In the business world, this grammar point is absolutely essential. During meetings, presentations, and in written proposals, professionals must constantly justify their strategies and decisions. You will hear phrases like 'based on market research' (市場調査に基づいて) or 'based on last year's sales data' (昨年の売上データに基づいて). Using this expression demonstrates logical thinking and a data-driven approach, which are highly valued in Japanese corporate culture.

Business Contexts

Used in proposals, reports, and meetings to justify decisions using data or company policy.

Academic and scientific settings also rely heavily on ～に基づいて. Whether it is a university lecture, a research paper, or a scientific documentary, the need to cite foundations and evidence is constant. Researchers will explain that their hypotheses are 'based on previous studies' (先行研究に基づいて) or that their conclusions are 'based on experimental results' (実験結果に基づいて). The noun-modifying form (に基づく) is particularly prevalent in academic writing to define complex concepts.

Another common area is in the realm of entertainment and media, specifically when discussing the origins of a creative work. At the beginning of movies, dramas, or books, you will often see or hear the disclaimer 'This story is based on true events' (この物語は実話に基づいています). This usage bridges the gap between the formal origins of the grammar point and its application in everyday pop culture, making it highly recognizable even to lower-level learners.

Legal and Official Documents

Appears constantly in contracts, terms of service, and government notices.

Finally, you will encounter it in everyday administrative situations, such as dealing with city halls, banks, or customer service. If a clerk explains why a certain fee is required or why an application was rejected, they will often cite a rule or regulation using this phrase. For example, 'Based on the regulations, this document is required' (規定に基づいて、この書類が必要です). Being able to comprehend this phrase helps you navigate life in Japan more smoothly, as it clarifies the rules governing administrative procedures.

While ～に基づいて is a straightforward grammar point structurally, learners frequently make semantic errors by confusing it with other similar-sounding or conceptually related expressions. The most prevalent mistake is using it to describe the physical materials used to make something. Because the English translation 'based on' or 'made from' can sometimes overlap, learners might attempt to say 'This cake is based on chocolate' using に基づいて. This is entirely incorrect in Japanese.

Mistake 1: Physical Materials

Using に基づいて for physical ingredients instead of で or から.

As emphasized previously, に基づいて requires an abstract foundation—a rule, a concept, data, or a story. It cannot be used for tangible ingredients. If you want to say a house is made of wood, you must use 木で作られている, not 木に基づいて作られている. If you want to say a movie is based on a novel, however, 小説に基づいて is perfectly acceptable because the novel represents an abstract story or concept, not a physical building material.

Another common error involves confusing に基づいて with に沿って (ni sotte). While both can translate to 'in accordance with' or 'following,' their nuances are distinct. に基づいて implies a foundation from which an action originates or is built upon. に沿って implies a line or a path that an action follows closely. For example, you make a plan 'based on' data (データに基づいて), but you execute the project 'along the lines of' or 'in accordance with' the manual (マニュアルに沿って). Using them interchangeably can sound unnatural.

Mistake 2: Confusing with に沿って

Failing to distinguish between a 'foundation' (基づいて) and a 'path/guideline' (沿って).

Learners also sometimes confuse it with に従って (ni shitagatte), which means 'to obey' or 'to follow instructions.' While you might act 'based on' a rule (規則に基づいて), using 規則に従って emphasizes the act of obedience and compliance rather than the rule being the logical foundation of your action. If a police officer gives you an order, you act に従って (obeying), not に基づいて (based on). The distinction lies in whether you are logically deriving an action from a source, or simply doing what you are told.

A structural mistake occurs when learners forget to change the form when modifying a noun. It is incorrect to say データに基づいて結論 (a conclusion based on data). Because 結論 is a noun, the preceding grammar must be in the noun-modifying dictionary form: データに基づく結論. This is a very common error in writing and speaking, as learners get used to the te-form and apply it universally. Always check the word immediately following the grammar point.

Mistake 3: Noun Modification Error

Using the te-form (に基づいて) directly before a noun instead of the dictionary form (に基づく).

Lastly, learners sometimes use this formal expression in overly casual situations, resulting in a mismatch of register. Saying 'I chose this restaurant based on my friend's recommendation' using 友達のおすすめに基づいて sounds stiff and unnatural. In casual conversation, it is much better to simply use で or から (友達のおすすめで選んだ). Reserve に基づいて for objective data, rules, and formal contexts to maintain natural Japanese phrasing.

To achieve fluency, it is crucial to distinguish ～に基づいて from its synonyms and related grammar points. Japanese has several expressions that translate to 'based on,' 'using as a basis,' or 'in accordance with,' but each carries a specific nuance that dictates its appropriate usage. The most closely related expression is ～をもとにして (wo moto ni shite). Both share the concept of a 'foundation' (moto), but they are used differently.

～をもとにして

Used when taking raw material, an idea, or an existing work and creating something new from it.

While に基づいて is used for abstract foundations like laws, data, and rules to justify an action or decision, をもとにして is used when you take a specific source material and transform it into a new creation. For example, if a movie is an adaptation of a novel, you would typically say 小説をもとにして映画が作られた (The movie was made based on the novel). It highlights the creative process of taking an original source and molding it. に基づいて sounds more rigid and analytical.

Another similar expression is ～に沿って (ni sotte), which translates to 'along with' or 'in accordance with.' As discussed in the Common Mistakes section, に沿って implies following a pre-existing line, path, manual, or guideline without deviating from it. If you are acting に基づいて, you are using the foundation to make your own logical judgments. If you are acting に沿って, you are simply following the established track. You make a plan 'based on' (に基づいて) the budget, but you execute the plan 'in accordance with' (に沿って) the schedule.

～に沿って

Following a path, guideline, or manual closely without deviation.

～を踏まえて (wo fumaete) is an advanced (B2/C1) grammar point that is often compared to に基づいて. 踏まえる literally means 'to stand on' or 'to step on.' Metaphorically, it means 'taking into account' or 'bearing in mind.' When you do something を踏まえて, you are acknowledging past experiences, current situations, or specific facts, and keeping them in mind as you make a decision or take action. It is less about a strict logical derivation (like に基づいて) and more about comprehensive consideration of various factors.

～に応じて (ni oojite) translates to 'depending on' or 'in accordance with.' This expression is used when an action or state changes flexibly in response to a variable condition. For example, 'The price changes depending on the season' (季節に応じて価格が変わる). This is entirely different from に基づいて, which implies a fixed, unmoving foundation. に応じて implies adaptability and proportional change based on external factors like age, experience, or weather.

～に応じて

Changing flexibly in response to a variable condition (depending on).

Finally, the simple particle で (de) can sometimes function similarly in casual speech. When you say 自分の判断で決めた (I decided based on my own judgment), the で acts as the basis or method of the decision. While it lacks the formal weight and explicit 'foundational' nuance of に基づいて, it is the most natural choice for everyday, non-academic, non-business conversations. Mastering when to use the formal に基づいて versus the casual で is a key marker of Japanese proficiency.