For five days that straddle the end of October and the start of November, the flood plain of the Kase River in Saga fills with hot-air balloons — more than a hundred of them, flown by pilots from some twenty countries. It is the largest event of its kind in Asia, and around eight hundred thousand people come to watch the autumn sky over the Saga plain fill with color.

The competition is, at heart, a contest of reading the wind. A balloon has no steering; a pilot can only rise or fall, hunting through the layered air for a current moving toward the target on the ground below. Whether the balloons fly at all is decided each morning by the sky itself, by the wind and the weather. This is part of the appeal — every session is improvised, shaped by conditions no one controls. From below, it looks serene. For the pilots, it is anything but.

The most photographed moment comes at night, in the tethered glows. The balloons stay grounded, and the pilots fire their burners in sequence, so that the great envelopes light from within, a row of luminous spheres standing on the dark riverbed.

A temporary railway station opens for the duration, which tells you something about the scale. But the essential experience is simpler than logistics: you stand on a riverbank on an autumn morning and watch a hundred balloons lift off at once, and give yourself over, as the pilots must, to the wind.