Demon Slayer is one of the most successful anime in the world.
Due to the popularity of the series, it broke the two-decade-long box office record of Spirited Away in Japan.
Before the release of Demon Slayer: Infinity Train, Spirited Away remained the highest-grossing anime movie in Japan, but shortly after the release of Demon Slayer movie, the tables were quickly turned.
The season of the series was but a prologue.
It wasn't until the movie that the story finally started shape and gave away hints of the secrets behind the Kamado family.
The second season of the series is arguably the most highly anticipated movie of the year and we have no doubt that it will be just as amazing.
The season will unravel secrets about Tanjiro's new powers.
But before that, let us first discuss the true meaning and history behind Tanjiro's Hanafuda earrings.
We should warn you that this article will contain lots of spoilers from the manga.
What is Sun Breathing Technique?
Sun Breathing Technique has not been fully revealed in the anime yet.
Even when Tanjiro first used the technique, he called it "Hinokami Kagura".
It means "Dance of the Fire God".
For generations, members of the Kamado family prayed to the sun god by performing a special dance continuously from sunset to sunrise at the start of each year.
It is an extremely difficult dance, in which Tanjiro's father excelled in.
However, what Tanjiro's father never revealed was that the dance was created using the twelve forms of the Sun Breathing Technique.
All these forms make up the world's first breathing technique that was used to fight against demons.
All the other breathing techniques are just branches of Sun Breath.
The members of the Kamado family are the direct descendants of the Sun Breathing Technique.
This is also the reason Nezuko's blood demon art is related to fire.
How are Hanafuda Earrings and Sun Breathing Technique related?
In episode 19, we saw glimpses of Tanjiro's childhood with his father.
He was wearing the same earrings as Tanjiro and performed the Hinokami Kagura.
On his deathbed, he told Tanjiro about a certain breathing technique that would keep the user from getting exhausted.
By mastering the correct way to breathe, the user will be able to dance forever without letting the cold bother him.
He also said that he wished for Tanjiro to inherit the ceremonial dance and the pair of earrings as a gift.
Hanafuda earrings don't have any powers to speak of but it acts as a symbol that the one wearing them is the user of the original breathing style.
There is only one pair of such earrings which was passed down to the Kamado family and ultimately became Tanjiro's.
In the manga, Tanjiro was the last person who inherited the earrings.
Sun breathing technique was created by a demon slayer about five centuries ago.
He was the first owner of the earrings and the only one feared by Muzan.
Even centuries after the technique creator's death, Muzan still fears the man and aims to kill anyone related to the earrings.
Why Was Tanjiro the Sole Inheritor of Hanafuda Earrings Among his Siblings?
As mentioned earlier, Tanjiro's father personally gave the earrings to Tanjiro.
But the suspense remains why Tanjiro was fit to wear the earrings among six siblings.
A logical guess would be that Tanjiro was the oldest son. But there was another reason behind it.
The mark on the top right of Tanjiro's forehead is the same as his father and the original owner of hanafuda earrings.
Tanjiro believed it to be caused by getting burned while saving his brother from a falling brazier.
However, the truth is that it is a demon slayer mark. It keeps changing shape every time Tanjiro becomes more powerful in the manga.
A few other Hashira were also able to obtain the demon slayer mark in the manga during their training.
However, the mark on Tanjiro's forehead directly implies that he is the inheritor of the sun breathing technique.
Although his father wasn't around when Tanjiro got the mark, we believe he must have known from the start that Tanjiro will be the inheritor.
Why is Muzan scared of Hanafuda earrings?
This is one of the best plots in the manga.
The original owner of hanafuda earrings and the creator of the sun breathing technique was the most powerful man who ever lived.
Muzan once considered the man a monster. Sun breathing is the second greatest weakness of Muzan.
The man who created the technique was Yoriichi Tsugikuni. He was able to defeat Muzan in a one-on-one fight, but couldn't kill him.
Muzan sustained serious injuries which never healed and kept burning him to this day.
Muzan claimed that even though the world condemns him as a monster, the real monster was actually Yoriichi.
In the anime, we only catch a glimpse of Yoriichi's silhouette where he was standing and looking down on Muzan.
It was most likely the moment when Muzan lost against him.