The Japanese Pressure Cooker

Not the insane work ethic that causes them to blow their tops in private, the CC refers to the otoshi-buta which is a particularly elegant concept.

Basically it's a wooden "drop lid" that sits right inside the pot on top of the vegetables or meat that you are simmering in dashi.

The idea is simple. It raises the temperature of the water above 100°C so that food cooks faster. In this process, it also allows for caramelization of the sugars are added first in the Japanese process. Also, the food stuff doesn't roll around in the boiling water which allows control of the texture because the food doesn't get "beat up".

You don't really need this specialized instrument though.

Classically trained French chefs use a similar technique. They advise you to make a simple round out of parchment paper and place it in top of whatever you are simmering.

In the modern world, aluminum foil will also do the work perfectly adequately.

If you've never seen this technique before, it seems wondrous (faster! tastier! magic!) but it's just plain ol' physics at work.