kono supootu no ruuru ha kantansou ni mieru keredo, zissai ni yatte miru to sukosi muzukasii.

Here, の links two nouns:

• このスポーツ = this sport
• ルール = rules

So このスポーツのルール means the rules of this sport or this sport’s rules.

It works a lot like of or apostrophe-s in English.

は marks the topic of the sentence.

So in:

• このスポーツのルールは...

the speaker is saying, as for the rules of this sport...

Everything after that comments on those rules. In English, we often do not mark the topic so clearly, but in Japanese this is very common.

簡単そう means looks easy or seems easy.

It is made from:

• 簡単 = easy, simple
• 〜そう = looks/seems like

So:

• 簡単そう = seems easy / looks easy

This 〜そう is used when something appears that way from what you see or sense.

In 簡単そうに見える, the に turns 簡単そう into an adverb-like form so it can modify the verb 見える.

• 簡単そう = easy-looking
• 簡単そうに見える = appears easy / looks easy

You can think of it as:

• Xそうに見える = looks as if it is X

This is a very common pattern.

The difference is certainty.

• 簡単 = is easy
• 簡単そう = looks easy / seems easy

So 簡単そう does not say the sport is actually easy. It only says that it appears easy at first.

That contrast is important, because the second half of the sentence says that in reality it is a little difficult.

けれど means but, although, or though.

In this sentence, it connects two contrasting ideas:

• it looks easy
• but it is actually a little difficult

So the flow is:

• It looks easy, but when you actually try it, it’s a little difficult.

けれど is a very common, natural way to make this kind of contrast. It often sounds a bit softer than でも or しかし.

実際に means actually, in reality, or in practice.

• 実際 = reality / actual situation
• 実際に = actually / in reality

The に makes it function adverbially, so it describes how the action is being considered:

• 実際にやってみる = actually try doing it / try it in real life

So the sentence contrasts appearance with real experience.

In this sentence, みる is not the literal to see.

The pattern 〜てみる means:

• to try doing something

So:

• やる = do
• やってみる = try doing it

Here it means something like actually try playing/doing the sport.

This is one of the most common grammar patterns in Japanese:

• 食べてみる = try eating
• 読んでみる = try reading
• 使ってみる = try using

Because やる is being put into the て-form.

• dictionary form: やる
• て-form: やって

Then it combines with みる:

• やってみる = try doing

This is standard conjugation for a -る verb of this type, like:

• とる → とって
• なる → なって
• やる → やって

Here, と is a conditional marker meaning something like:

• when
• if
• once

So:

• 実際にやってみると = when you actually try it / once you actually try it

In this kind of sentence, 〜てみると often introduces something you discover after trying something.

So the nuance is:

• it looks easy at first,
• but when you actually try it, you find that it is a little difficult.

少し means a little or slightly.

So:

• 少し難しい = a little difficult

It softens the statement. The speaker is not saying the sport is extremely hard, only that it is harder than it first appears.

A similar word is ちょっと, which could also work in casual speech, but 少し sounds a bit more neutral and straightforward here.

Japanese often leaves the subject unstated when it is clear from context.

Here, 少し難しい means that actually doing/playing the sport is a little difficult.

It does not mean the written rules themselves are difficult. The sentence says:

• the rules look easy,
• but trying the sport in practice is a little difficult.

So the idea shifts naturally from the rules to the actual experience of doing it.

A fairly literal breakdown would be:

• このスポーツのルールは = As for the rules of this sport,
• 簡単そうに見えるけれど、 = they look easy, but
• 実際にやってみると = when you actually try doing it,
• 少し難しい。 = it is a little difficult.

A natural English translation would be something like:

• The rules of this sport look simple, but when you actually try it, it’s a little difficult.