The koi is Japan's great emblem of grit rewarded. The legend runs that a carp which battles its way up a raging river and leaps the waterfall at the Dragon Gate is transformed into a dragon — so the fish became a byword for perseverance, ambition, and the long hard swim to success. It's why carp streamers still fly over Japanese rooftops every Boys' Day, one for each child, a quiet wish that they'll grow strong enough to make the climb.

Here that emblem gets the finest hand in Japanese art. This koi comes from the brush of Hokusai — the man who would go on to create the Great Wave and become the most famous artist his country ever produced — working in an illustrated book decades before that fame arrived. Even so, the mastery is unmistakable: a muscular, twisting swimmer caught mid-surge, all coiled power and forward drive. It's the fish of determination drawn by an artist who embodied exactly that, sketching obsessively into his ninth decade in pursuit of the perfect line.

Koi (鯉), from the picture book Ehon teikun ōrai (絵本庭訓往来, Illustrated Book of Domestic Manners) 1828.

Katsushika Hokusai (葛飾北斎, 1760-1849)