The process of drying the ume is every bit as essential as the previous stages. After all, they will be kept for a whole year before they are taken out and eaten.
That's why they're called ume-boshi — literally "ume dried" — rather than ume-zuke ("ume pickled").
On the evening of Day 3, we didn't put the ume back in the juice. On Day 4, when we put them out for their final day, they are ready to absorb a last blast of the sun's rays.
By the afternoon they are ready: pink, plump but gently wrinkled, a delicate whitish haze of salt now faintly visible on the surface, soft and juicy still inside...
They're ready to be packed away – very carefully, very gently – into jars.
Stashed away at the back of our pantry, they'll be given one whole year to age and mature before we start to use them (just as I do with umeshu). That's the way to mellow out the salty, sour flavours a bit.
It's also the tradition, the way it's been taught by the old-timers, the way it's been handed down through the generations. And who are we to mess with that?
[UPDATE, July 2014 here…]