itizikyuumeisyoti de kyuumei no rensa ga hazimaru.

A common reading is:

いちじ きゅうめい しょち で きゅうめい の れんさ が はじまる。

Word by word:

• 一次救命処置 = いちじきゅうめいしょち
• で
• 救命 = きゅうめい
• の
• 連鎖 = れんさ
• が
• 始まる = はじまる

In medical contexts, 一次救命処置 often corresponds to basic life support (BLS) or primary emergency life-saving procedures.

一次救命処置 is a technical term.

Breakdown:

• 一次 = primary / first-stage
• 救命 = life-saving
• 処置 = treatment / measures / procedures

So the whole phrase means something like:

• primary life-saving procedures
• initial emergency life-saving treatment
• in many contexts, basic life support

The exact English translation depends on the source, but it refers to the first actions taken to save someone’s life, such as CPR and related emergency response steps.

Here, で shows the means, occasion, or starting point/context through which something happens.

So 一次救命処置で means something like:

• with basic life support
• through primary life-saving procedures
• at the stage of primary life-saving treatment

It is not the location marker で here. It is closer to by means of / through / with.

So the sentence is saying that the chain of survival begins with/through these initial life-saving procedures.

救命の連鎖 literally means the chain of life-saving.

• 救命 = saving lives / life-saving
• 連鎖 = chain
• の links the two nouns

In English, this is usually translated more naturally as:

• the chain of survival

The particle の has a broad noun-linking function. Depending on context, it can mean:

• possession
• description
• category
• purpose
• relation

Here it links 救命 and 連鎖 so that 連鎖 is a chain related to life-saving.

Because 始まる is an intransitive verb.

• 始まる = to begin / to start
• 始める = to begin something / to start something

In this sentence, 救命の連鎖 is the thing that begins by itself grammatically, so it takes が:

• 救命の連鎖が始まる = the chain of survival begins

If you used 始める, you would need someone to start it:

• 医師が処置を始める = The doctor begins the treatment

So が始まる is the correct pattern here.

が marks 救命の連鎖 as the grammatical subject of 始まる.

• 救命の連鎖が始まる = the chain of survival begins

Using が is natural because the sentence is presenting the event: the chain of survival starts.

If you changed it to は, it would feel more like setting 救命の連鎖 up as the topic for contrast or discussion:

• 救命の連鎖は始まる = As for the chain of survival, it begins...

That is not impossible, but it sounds less natural here unless there is special context. The original with が is the straightforward choice.

Yes. 始まる is the plain non-past form.

In Japanese, the non-past form can express:

• a present/general truth
• a future event
• a habitual action

So 救命の連鎖が始まる can mean:

• the chain of survival begins
• the chain of survival will begin

In this kind of slogan-like or explanatory sentence, it usually expresses a general truth:

• The chain of survival begins with basic life support.

No extra subject is needed.

The explicit subject is already there:

• 救命の連鎖が = the chain of survival

Japanese often omits information when it is not necessary, but in this sentence the main subject of the verb is present. What is omitted, if anything, is only broader context, such as:

• in an emergency
• for a patient in cardiac arrest
• from this first step

Japanese often relies on context more than English does.

Because it uses compact, technical noun phrases:

• 一次救命処置
• 救命の連鎖

This style is common in:

• medical materials
• training manuals
• public safety campaigns
• posters and headings

Instead of sounding conversational, it sounds like an educational statement or slogan:

• Basic life support starts the chain of survival.

In everyday conversation, people might use simpler wording.

Yes, depending on context.

The particle で can sometimes blur together ideas like:

• in
• at
• through
• by means of

So 一次救命処置で救命の連鎖が始まる can suggest:

• the chain of survival begins with primary life-saving procedures
• the chain of survival begins at the stage of basic life support
• the chain of survival begins through those first interventions

English usually picks one phrasing, but the Japanese can carry several closely related nuances at once.

Yes, it is closely related to a standard emergency-medicine phrase.

A very common English term is:

• chain of survival

Japanese often expresses this as:

• 救命の連鎖

So while the phrase is understandable literally, it is also a recognized concept in emergency care. That is why the sentence may sound more natural in medical or training contexts than if you tried to interpret it as an everyday phrase.

It is very natural.

The structure is:

• 一次救命処置で = with/by means of primary life-saving procedures
• 救命の連鎖が = the chain of survival
• 始まる = begins

This follows a very common Japanese pattern:

[context/means] + [subject] + [verb]

So the sentence is neatly organized as: With basic life support, the chain of survival begins.

That word order is especially common in written explanations and formal statements.