Thousand Year Old Eggs

The thought of eating an egg that is a thousand years old is enough to make most people lose their appetite. To me, thousand year old eggs remind me of rice porridge, because that is usually what I eat them with. I don't eat them often, but when I do, I can usually eat only one egg at most. Above is a picture of the thousand year old egg in it's shell, and the picture below shows the inner part of the egg along with it's jelly like outer part.

They are often referred to as 1000 year old eggs or 100 year old eggs, but are not nearly that old. They are in actual fact, simply preserved duck eggs. The inner yolk part is firm and rich in texture and the outside is similar to jelly.
Sometimes, the inner part is somewhat runny and I always thought it was because some preserved duck egg yolks were meant to be that way. However, I discovered that if the egg is boiled for 8 minutes or so, then the egg would firm up, both on the outside and the inside, similar to a hardboiled egg.