hiokosi ha muzukasii.

It is read:

ひおこし は むずかしい。

A few notes:

• 火起こし = ひおこし
• は is written ha but pronounced wa when it is the topic particle
• 難しい = むずかしい

So the whole sentence sounds like:

ひおこし は むずかしい。

火起こし means fire-starting or making a fire.

It refers to the act or process of getting a fire going, especially from scratch. Depending on context, it can mean things like:

• starting a campfire
• lighting charcoal
• making fire in a traditional way

It is a noun here.

It is made from:

• 火（ひ） = fire
• 起こし（おこし） = starting / raising / causing

So 火起こし literally has the sense of fire-starting.

This kind of noun is very common in Japanese: a verb stem or related form combines with another element to make a noun describing an activity.

You may also see the related verb expression:

• 火を起こす = to start a fire

So:

• 火を起こす = verb phrase
• 火起こし = noun meaning fire-starting

は marks the topic of the sentence.

So 火起こしは難しい means something like:

• As for fire-starting, it is difficult
• Fire-starting is difficult

The sentence is talking about 火起こし as the topic, and then saying something about it: it is difficult.

This is extremely common in Japanese:

• A は B
• As for A, it is B

This is one of the standard special pronunciations in Japanese particles.

When は is used as the topic particle, it is pronounced わ.

So:

• written: 火起こしは難しい
• pronounced: ひおこし わ むずかしい

This only applies when は is being used as a particle. In other words, the spelling stays the same, but the pronunciation changes.

Both can appear in similar sentences, but they give different nuance.

• 火起こしは難しい。
  = Fire-starting is difficult / As for fire-starting, it’s difficult

This sounds like a general statement about the topic.

If you said:

• 火起こしが難しい。

that would sound more like It is fire-starting that is difficult or Fire-starting is the difficult part, depending on context.

Very roughly:

• は = presents the topic, often broader or contrastive
• が = marks the subject more directly, often with a sense of identification or focus

For a simple standalone statement like this, は is very natural.

難しい（むずかしい） is an i-adjective.

That means it ends in -い and can function directly as a predicate:

• 難しい。 = is difficult

So in this sentence:

• 火起こし = topic noun
• は = topic marker
• 難しい = predicate adjective

Japanese does not need a separate word for is in this plain-style sentence.

In Japanese, adjectives like 難しい can end the sentence by themselves.

So:

• 火起こしは難しい。

already means:

• Fire-starting is difficult.

You do not need a separate is the way you do in English.

If you want to make it more polite, you can add です:

• 火起こしは難しいです。

That still means the same thing, but in a more polite style.

It is in the plain style:

• 火起こしは難しい。

A polite version would be:

• 火起こしは難しいです。

Both mean the same thing. The difference is tone:

• 難しい。 = plain
• 難しいです。 = polite

The plain version is common in writing, casual speech, explanations, and dictionary-style examples.

Yes. That is a very natural alternative.

• 火を起こすのは難しい。
• Starting a fire is difficult.

This version uses the verb phrase:

• 火を起こす = to start a fire

and then turns it into something noun-like with の:

• 火を起こすの = the act of starting a fire

Compared with 火起こしは難しい, this version may feel a little more explicitly verbal, while 火起こし is a compact noun meaning fire-starting.

Both are natural.

It depends on context.

火起こし often suggests getting a fire going, especially in practical situations such as:

• camping
• barbecue charcoal
• traditional fire-making
• survival skills

In some contexts, it can feel more hands-on than simply lighting something with a switch or lighter.

So while the exact English translation may vary, fire-starting is often the safest broad translation.

The spaces are usually just for learners.

Normal Japanese writing would usually be:

火起こしは難しい。

Japanese normally does not use spaces between words the way English does.

So the spaced version is just there to make the structure easier to see:

• 火起こし
• は
• 難しい

Yes, は can sometimes carry a contrastive feeling.

So depending on context, 火起こしは難しい could mean:

• Fire-starting is difficult
  or
• Fire-starting, at least, is difficult

For example, if someone is talking about survival skills, this could imply:

• finding wood is easy, but starting the fire is difficult

However, without special context, the most natural reading is just the neutral one:

• Fire-starting is difficult.