始まる vs. 開始する: Natural Beginnings and Formal Starts in Japanese

Introduction

The Japanese words 始まる (hajimaru / to begin or start) and 開始する (kaishi suru / to commence or initiate) both describe the beginning of something.

Because their meanings are so similar, many Japanese learners assume that 開始する is simply a more formal version of 始まる.

That idea is partly correct, but it does not explain the whole difference.

始まる is commonly used when an event, period, activity, or situation begins. It is natural in everyday conversation and focuses on the thing that begins.

開始する is more formal and is often used when a person, company, government agency, or other organization deliberately starts an activity, service, operation, or procedure.

These words are close in meaning, but using the wrong one can make a sentence sound overly formal or grammatically unnatural.

Let us begin with some common mistakes and learn how to correct them.

Common Mistakes

Consider the following sentence:

もうすぐ春が開始します。
Spring will commence soon.

The meaning is understandable. The speaker wants to say that spring is coming soon.

However, 春が開始する sounds unnatural in Japanese. Spring is not a project, service, or procedure that someone officially launches.

A more natural sentence is:

もうすぐ春が始まります。
Spring will begin soon.

Now look at another example:

映画が7時に開始します。
The movie will commence at seven.

This sentence is understandable and may appear in a formal schedule or announcement. In an ordinary conversation, however, it sounds unnecessarily official.

When speaking with a friend, the following sentence is more natural:

映画は7時に始まります。
The movie starts at seven.

開始する is not always grammatically wrong in such situations. The problem is often that its level of formality does not match the situation.

Why Do These Sentences Sound Unnatural?

The difference is not only that 始まる is casual and 開始する is formal. The two words also tend to create different sentence structures.

始まる is an intransitive verb. It describes something beginning on its own or entering its starting state.

授業が始まる。
The class begins.

会議が始まる。
The meeting begins.

夏休みが始まる。
Summer vacation begins.

The focus is on what begins. For this reason, 始まる is commonly used with the particle が.

開始する is often used when a person or organization deliberately starts an activity.

会社が新しいサービスを開始する。
The company launches a new service.

担当者が受付を開始する。
The person in charge begins accepting applications.

政府が新しい制度の運用を開始する。
The government begins operating a new system.

In these sentences, the structure is usually “someone starts something,” so 開始する is commonly used with the particle を.

In this respect, 開始する often behaves more like 始める (hajimeru / to start something) than 始まる.

Compare these two sentences:

サービスが始まる。
The service begins.

会社がサービスを開始する。
The company launches the service.

Both sentences describe the same event, but the viewpoint is different.

サービスが始まる focuses on the service itself.

会社がサービスを開始する focuses on the company that launches the service.

If you replace only the verb without considering this difference in viewpoint, the result may sound unnatural.

Natural Corrections

Let us correct the earlier examples.

Mistake 1

もうすぐ春が開始します。
Spring will commence soon.

Natural Version

もうすぐ春が始まります。
Spring will begin soon.

Spring is not something that a person or organization deliberately launches. It is a natural seasonal change, so 始まる is the appropriate choice.

Mistake 2

映画が7時に開始します。
The movie will commence at seven.

Natural Version in Everyday Conversation

映画は7時に始まります。
The movie starts at seven.

When simply telling someone the starting time of a movie, 始まる sounds natural and conversational.

In an official announcement by a cinema, however, 開始する may be appropriate:

7時より上映を開始します。
The screening will begin at seven.

Here, the cinema is formally announcing that it will begin the screening. The object is 上映 (jōei / screening), an organized activity, so 開始する fits the context.

Another Easily Confused Sentence

来月から新しい生活を開始します。
I will commence a new life next month.

This is grammatically possible, but it sounds rather formal in a personal conversation. It may sound as though the speaker is announcing a business project.

A more natural sentence is:

来月から新しい生活が始まります。
My new life will begin next month.

When the speaker wants to emphasize their own decision to build a new life, 始める is also possible:

来月から新しい生活を始めます。
I will start a new life next month.

The choice among 始まる, 始める, and 開始する depends on the viewpoint of the sentence.

The Basic Difference Between 始まる and 開始する

始まる describes an event, activity, period, or situation entering its beginning stage.

It is widely used in both spoken and written Japanese and can describe classes, movies, games, seasons, jobs, events, and many other things.

授業が始まる。
The class begins.

試合が始まる。
The game begins.

新しい一年が始まる。
A new year begins.

開始する is commonly used when a person or organization deliberately and often officially begins an activity, operation, procedure, service, investigation, or system.

It frequently appears in company announcements, news reports, government notices, business documents, and operating instructions.

受付を開始する。
To begin accepting applications.

販売を開始する。
To begin sales.

調査を開始する。
To launch an investigation.

システムの運用を開始する。
To begin operating the system.

The main points can be summarized as follows:

• 始まる focuses on the event or situation that begins.
• 開始する often focuses on the person or organization starting an activity.
• 始まる is common in everyday conversation.
• 開始する is common in formal announcements, news, business, and administration.
• 始まる is often used in the pattern 「何かが始まる」.
• 開始する is often used in the pattern 「誰かが何かを開始する」.

The passive form 開始される (kaishi sareru / to be commenced or launched) is also common in formal Japanese.

試験が開始されました。
The examination has begun.

新しいサービスが開始されました。
A new service has been launched.

The passive form allows the speaker to report the event formally without identifying the person or organization responsible for starting it.

Learn the Difference Through Examples

1. 授業が始まりました。

先生が教室に入ると、すぐに授業が始まりました。
As soon as the teacher entered the classroom, the lesson began.

The sentence describes the lesson itself beginning. This is an ordinary situation, so 始まる is the most natural choice.

2. 新しい生活が始まります。

来月から東京で新しい生活が始まります。
My new life in Tokyo will begin next month.

This sentence describes the beginning of a new stage of life. Because it is a natural and personal change, 始まる sounds better than 開始する.

3. 雨が降り始めました。

駅を出たところで、雨が降り始めました。
It began to rain just as I left the station.

In this situation, Japanese normally uses 降り始める (furi-hajimeru / to begin to fall) rather than 雨が始まる.

The pattern “verb stem + 始める” expresses the beginning of an action.

4. 会社が新サービスの提供を開始しました。

当社は、7月から新しい学習サービスの提供を開始しました。
Our company began offering a new learning service in July.

The company deliberately launched a planned service. Because this is a formal corporate announcement, 開始する is natural.

5. 受付を開始します。

午前9時から、試験の申し込み受付を開始します。
Applications for the examination will be accepted from 9:00 a.m.

An organizer or staff member is officially beginning the application process. This is a planned administrative action, so 開始する is appropriate.

6. まもなく試合が始まります。

選手たちが会場に入りました。まもなく試合が始まります。
The players have entered the venue. The game will begin shortly.

The sentence focuses on the game itself beginning. In ordinary conversation or sports commentary, 始まる sounds natural.

7. ただいまより式典を開始します。

皆様、お待たせいたしました。ただいまより記念式典を開始します。
Thank you for waiting. We will now commence the commemorative ceremony.

The host or organizer is formally declaring the beginning of a ceremony. 開始する creates the official and ceremonial tone required in this situation.

8. 販売が始まりました。

今日から、夏限定商品の販売が始まりました。
Sales of the limited-edition summer products began today.

The sentence focuses on the fact that the sales period has begun. From the customer’s point of view, 販売が始まる is natural.

When the company’s action is emphasized, the sentence changes:

会社は今日から夏限定商品の販売を開始しました。
The company began selling its limited-edition summer products today.

Both sentences describe the same event, but the viewpoint is different.

How These Words Appear in JLPT Questions

In JLPT vocabulary and reading questions, 始まる and 開始する may both appear as possible answers because their basic meanings are similar.

To choose the correct answer, do not look only at the English translation “to start.” Check the particle, the subject, and the level of formality.

Consider this sentence:

来週から、新しいサービスの提供を（　　　）。
Starting next week, we will (　　　) the provision of a new service.

If the options include 始まる and 開始する, the correct answer is 開始する.

来週から、新しいサービスの提供を開始する。
We will begin providing a new service next week.

The noun phrase 新しいサービスの提供 is followed by を. Someone or some organization is deliberately starting the activity, so 開始する is appropriate.

Now consider this sentence:

来週から、新しいサービスが（　　　）。
A new service will (　　　) next week.

Here, 始まる is the natural answer.

来週から、新しいサービスが始まる。
A new service will begin next week.

The service itself is the subject of the sentence.

The tone of the passage also matters.

夏休みが来週から開始します。
Summer vacation will commence next week.

Although understandable, this sounds too formal for an ordinary description of school life.

The natural sentence is:

夏休みが来週から始まります。
Summer vacation begins next week.

On the other hand, 開始する is common in official announcements:

市は来月から新しい支援制度の運用を開始します。
The city will begin operating a new support program next month.

When answering JLPT questions, check these three points:

• If the thing itself begins and is marked by が, 始まる is usually natural.
• If a person or organization deliberately starts something marked by を, 開始する is often appropriate.
• In everyday contexts, 始まる is common; in official and planned contexts, 開始する is more likely.

The words may look almost identical in meaning, but the surrounding context reveals the correct answer.

Summary

始まる and 開始する both express the beginning of something, but they differ in viewpoint, sentence structure, and formality.

• 始まる describes an event, activity, period, or situation beginning.
• 開始する describes a person or organization deliberately and often officially starting an activity.
• 始まる commonly appears in patterns such as 「授業が始まる」.
• 開始する commonly appears in patterns such as 「授業を開始する」.
• 始まる is natural in everyday conversation.
• 開始する is common in announcements, business, administration, and news reports.

Do not choose between them simply because both can be translated as “to start.”

Ask yourself:

• What is beginning?
• Is someone deliberately starting it?
• Is the situation conversational or official?
• Does the sentence use が or を?

These questions will help you select the expression that sounds natural in context.

Understanding similar Japanese words requires more than memorizing dictionary definitions. You need repeated practice choosing the right expression in realistic sentences.

RJT (Rapid Japanese Training) helps you practice easily confused vocabulary and grammar through short JLPT-style questions. By answering regularly, you can develop the ability to notice subtle differences and avoid tempting but incorrect options.

Build a more natural sense of Japanese through focused practice:

https://rapid-jt.com/