I have known the name of Kakyo Girls' Academy since I was a small child.

A white, majestic school building in the Vories architectural style built in the Meiji era, showing no signs of age. A prestigious, five-year boarding school for girls aged 14 to 19.

The girls who pass through the gates all wear black sailor uniforms with deep crimson ribbons.

Daughters of old families. Young ladies of renowned houses. Children of families who have held wealth for generations.

Blessed with beauty and well-bred, these are girls who have known what it is to be watched by others since childhood. The public called them "flowers on a high peak."

Indeed, it is no wonder they were called so.

The girls of Kakyo were always as beautiful as flowers. However, flowers are beautiful only as long as they are viewed from afar. If you draw close, there are thorns.

Kakyo Girls' Academy has an ancient custom.

Its origins are said to date back to the pre-war era. The "Class S" culture that once flourished among schoolgirls. Times changed, the world changed, and while it transformed its appearance many times, it remains only in this academy to this day.

Its name is—

Hana-chigiri (The Flower Vow)

Hana-chigiri is when an upperclassman and a underclassman choose each other as their one and only, forming a bond of sisterhood.

The chosen upperclassman is the Hanamori (Flower Guardian). The chosen underclassman is the Raiko (Flower Bud).

The Hanamori guides the Raiko. The Raiko respects the Hanamori.

As they spend several years together, an affection that cannot be measured by outsiders eventually blossoms between the two.

They are not sisters by blood. But it is something thicker than blood, and at times, more cruel than blood.

There are three oaths in the Flower Vow.

1. You shall not entrust your heart to anyone else.
2. You shall leave no lies or secrets between each other.
3. You shall never forget each other for the rest of your lives.

Among them, only the last one has a slightly different meaning from the other two.

The Flower Vow does not end with graduation.

There are cases where different lives await each of them once they leave the academy.

Some spend their whole lives together. Some inherit their family estates, some marry into distant lands. Some start entirely different lives in towns whose names they do not know.

Even so, the Flower Vow alone does not end.

Once they have become sisters, they are sisters for life.

That is why the girls of Kakyo think the same thing in their hearts every time spring arrives.

Whose elder sister shall I become? Whose younger sister shall I become?

It is heavier than love and longer than marriage. To choose only one person in a lifetime. And once chosen, never to let go of that hand.

It is not easy to dissolve a Flower Vow.

Nay, even to desire such a thing is deeply abhorred at Kakyo. Therefore, there are girls who never form a vow with anyone even after finishing five years of academy life. It cannot be just anyone. Not because they are beautiful. Not because they are wise. Not because they are of good family.

It simply must be that person. Until they find such a partner, they remain as buds.

The girls of Kakyo study divided into four vocational branches.

「Goka」 (Flower Protection) Those who protect. Guard duty, management, exclusion, crisis management, etc. Physical ability and judgment are emphasized. After graduation, they join guard units for nobility, merchant houses, politicians, etc.

「Tenka」 (Flower Ceremony) Those who stand before others. Etiquette, social graces, diplomacy, languages, etc. After graduation, they become archivists for noble families, work in diplomatic relations, secretaries, tutors, etc.

「Bunka」 (Flower Literature) Those who know and record. Literature, history, law, accounting, cryptography, information gathering. After graduation, they work for secretaries, scribes, newspapers, publishers, etc.

「Ryoka」 (Flower Healing) Those who heal. Medicine, nursing, pharmacy, psychology, caregiving. After graduation, they work in hospitals, clinics, or as private doctors and nurses for noble families.

While studying in their four separate paths, the girls walk the same garden.

In spring, they look up at the blossoms. In summer, they listen to the cicadas. In autumn, they step on fallen leaves. In winter, they exhale white breath.

There is an old saying at Kakyo Girls' Academy.

"Flowers bloom only to fall."

The girls think it is a beautiful phrase.

But I do not think so. Flowers are not beautiful because they fall. I think they are beautiful because, knowing they will fall, they still take someone's hand.

I do not yet know how blissful and how terrifying it is to choose a person.

Today again, the old clock tower tolls the hour. Two girls walk through the garden where roses bloom.

One is a Hanamori. One is a Raiko.

"Hey."

Eh... ah, what is it?

"Have you decided on your Onee-sama yet?"

No, not yet.

"I've decided on my Onee-sama. She's a fourth-year—"