1. I like Admiral Yi Sunsin because he protected our country from Japanese.

2. I like Admiral Yi Sunsin because he saved our country from the Japanese invasion.

3. I like Admiral Yi Sunsin because he fought against the Japanese navy and protected our country.

4. I like Admiral Yi Sunsin because he broke many Japanese ships and won the naval battle several times.

5. I like Admiral Yi Sunsin because he protected our country from Japanese soldiers.

6. I like Admiral Yi Sunsin because he protected our country from Japanese Marines.
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I appreciate your help.
I have posted several sentences. Would you check them and correct errors? Do you have better sentences?

Everything looks good except the word ‘broke’ in 4. Which of these verbs would work best, Doyle think?

Sank
Destroyed
Blew up

Sorry! ... do you think?

7. He destroyed many Japanese ships.

8. He blew up many Japanese ships with guns.
9. He sank many Japanese ships.
10. He had his men sank many Japanese ships by using guns/with guns.
[Are they okay?]

7, 8, and 9 are OK.

10 ~~> He had his men sink many Japanese ships ...

I've reviewed the sentences you provided and made some corrections and improvements:

1. I admire Admiral Yi Sunsin for his role in protecting our country from the Japanese.

2. I have great admiration for Admiral Yi Sunsin because he successfully defended our country from Japanese invasion.

3. Admiral Yi Sunsin is a remarkable figure as he courageously fought against the Japanese navy, ultimately ensuring the safety of our country.

4. Admiral Yi Sunsin's naval prowess was truly remarkable. He decisively defeated numerous Japanese ships, emerging victorious in multiple battles.

5. I hold Admiral Yi Sunsin in high regard for his efforts in safeguarding our country from Japanese invasion forces.

6. Admiral Yi Sunsin played a crucial role in defending our country from Japanese marines, earning my utmost respect.

These sentences reflect a variety of ways to express your appreciation for Admiral Yi Sunsin while avoiding repetition.