Remove stems and wash plums in water twice then soak in a bowl of cold water overnight.

Drain plums, dunk in a bowl of vodka, and set out on a clean towel to dry.

Wash shiso leaves, remove tough stems, sprinkle with salt and massage leaves until they are limp.

Disinfect a container or jar with vodka that can hold all your plums.

Fill your pickling container with salt and plums by starting with a layer of salt, then a layer of plums, followed by a layer of shiso.

Repeat until all ingredients are used.

Weigh down plums with a clean plastic bag filled with water or another clean smaller jar filled with rocks and water. Cover the top with cheesecloth and secure with a rubber band.

Leave plums in a cool, dark area until they are soft and completely immersed in liquid (about 1-2 weeks).

If liquid is not completely covering plums, try increasing the weight.

Liquid should be about 1 inch above the top of the plums.

Leave the plums in the liquid about 2-3 weeks.

To dry, put the plums in a single layer and the shiso leaves in spread-out clumps separately on flat baskets.

Leave the baskets outside in a sunny place with good ventilation for about 3 days, turning them at least every 24 hours. At the end of the drying process, they should look wrinkly.

The umeboshi is now ready to eat - they can be eaten for up to 10 years (!) and grow in complexity over time.