When Kaoru was a little girl, around seven or eight years old, her father took her to the chrysanthemum fair at Daienji temple. The building itself was neither large nor impressive, yet the brightly colored mums and cheerful noise had drawn quite a crowd. Clinging tightly to her father's hand, Kaoru had stared about at the frilly plants, many of them taller than she, as their sweet yet earthy fragrance filled the air and reminded her, in some distant and nebulous fashion, of her mother. The unsought memory had created an ache in her chest and brought startled tears to her eyes, and perhaps because of the latter her father had been more indulgent than was his wont. Later, fingers and chin sticky from both chrysanthemum embossed monaka and leaf shaped namagashi, he'd taken her to see the best part of the festival: the kiku-ningyo. The so-called chrysanthemum puppets were wax figures dressed in elaborate costumes, all of which were fashioned out of flowers. Not just figures, either, but entire scenes. They'd stayed for hours, until Kaoru was absolutely certain she'd seen every last samurai, geisha, and hero.
Each year thereafter they attended the festival together, right up until the autumn before the Seinan War. In time, Kaoru grew old enough that she need not hold his hand, and had learned why the scent of flowering mums reminded her of her mother, but she never outgrew her fondness for seasonal sweets, or her fascination with the kiku-ningyo.
So it was that she insisted on attending the event with Kenshin, that first cool yet sunny autumn after Enishi's defeat. They were alive, and together, and she wanted to share something she'd always treasured as a child with the man who never got to be one. Especially since the freedom to live, to enjoy such frivolous pleasures, was so much a part of why he'd sacrificed his youth.
As they made their way along the busy streets, passing smiling adults and chattering children on their way to the temple, she felt that same almost nervous excitement of ten years before, when the entire experience had been new. And why shouldn't she? Visiting Daienji with Kenshin was new: the feel of her fingers cradled against his strong, sword calloused palm was both similar to, yet completely different from, the memory of clinging tightly to her father's hand. The taste of bean paste cookies and mochi confections was no less sweet, yet paled in comparison to the rush of sharing chrysanthemum wine to toast the future.
And despite all the joy the day would hold, Kaoru, like her father before her, would come to know that the best part of all was not the food or the excitement or even her own pleasure at the sights and sounds. It was, instead, the look of wonder on a loved one's face as they wandered hand-in-hand among the unlikely display of chrysanthemum figures.
Author's note: There is a tradition called kiku-wata which involves collecting dew from mum blossoms and using it to bathe the face and arms. I couldn't seem to find a way to fit it into the story other than by implication, but this is the reason Kaoru associates the fragrance of chysanthemums with her mother.