The autumn fireworks at Omagari are not a competition.

In August, this same riverbed hosts the contest that decides who makes the finest fireworks in Japan. Sixty thousand people, twenty-eight companies, a prize from the Prime Minister. In October, none of that. The local pyrotechnicians gather, choose a theme, and experiment.

They call it sozo hanabi - creation fireworks - and Omagari is where it began. Shapes that refuse to be circles. Forms that have no name yet.

Autumn air in Tohoku is clear in a way summer air never is. Colors arrive undiluted. Edges hold.

A night when fireworks makers light the sky for each other.