Zosui (porridge of rice and vegetables) (雑炊)

Zosui is made by simmering cooked rice again with meat, fish and shellfish, mushroom and vegetable, seasoned with soy sauce, miso, etc. Also, zosui is made by stewing cooked rice with the leftover soup of nabemono (a dish served in a pot at the table).

In ancient times, zosui was shown as '増水' (increased water), which probably had a strong connotation of increasing the volume of rice with water. It seems that after other ingredients were added to this 増水, kanji characters '雑炊' came to be used.

Difference between zosui and ojiya (rice gruel seasoned with miso or soy sauce)
Ojiya used to be the lady's language for zosui, but today it is sometimes recognized as different from zosui. However, the distinction is far from universal (the followings are examples).

Distinction by the conditions of rice

Zosui is made with cooked rice that is once washed before cooking in order to remove the surface starch, resulting in a light texture. For ojiya, cooked but unwashed rice is used.

Zosui is just heating ingredients with soup or not stewing them enough to extract water from them in order to leave the original shape of rice. For ojiya, ingredients are stewed to extract water and the original shape of rice is not left so much.

Distinction by seasoning

The one seasoned with miso is called ojiya.

Various kinds of zosui

Maru zosui (Japanese soft-shelled turtle porridge)

-The one made by simmering cooked rice in the soup left over mainly in marunabe (Japanese rice & soft-shelled turtle porridge).

Fugu-zosui (porridge of pufferfish, rice and vegetables)

-The one made by simmering cooked rice in the soup left over mainly in fuguchiri (Wild Balloon fish stew).

Tori zosui (Japanese rice & chicken porridge)

-The one made by simmering cooked rice in the soup left over mainly in chicken boiled plain.

Kani zosui (crab hotpot & rice porridge)

-The one made by simmering cooked rice in the soup left over mainly in kani nabe (crab hotpot).

Sukiyaki zosui(Japanese beef hot pot & rice porridge)

-The one made by simmering cooked rice in the soup left over mainly in sukiyaki.

Shabu-shabu zosui (thinly sliced meat boiled quickly with vegetable & rice porridge)

-The one made by simmering cooked rice in the soup left over mainly in shabu-shabu (thinly sliced meat boiled quickly with vegetables, and dipped in sauce).

In addition, the soup of oden oden (Japanese dish containing all kinds of ingredients cooked in a special broth of soy sauce, sugar, sake, etc.), vegetable soup and ramen soup can also be used.

Others
Okinawan cuisine Jyusi is thought to be a corruption form of zosui. However, both the usual takikomi gohan (mixed rice) and high moisture zosui are referred to as Jyusi.

There are several theories about the origin of ojiya, but according to researchers of the European dish, Spanish cuisine and Portuguese cuisine, it is thought to be derived from Spanish dish OLLA.

During trades with Spain and Portugal, and Christian missionary work from the end of the 16th century through the beginning of the 17th century, ojiya was believed to have been introduced to the Kansai region and parts west by the Jesuits and to Edo by the Franciscan monks, respectively. (It is highly possible that in both the cases ojiya had been introduced by the missionaries from Seville and Andalusia.

There are some dishes for which kanji was given later like Tempura, but similar to castella sponge cake, konpeito (confetti, candy), etc., kanji was not given for ojiya and it remained as its pronunciation, making people think it is a traditional Japanese dish.

In Spain, there are dishes of rice made with soup named '… caldoso,' 'arroz …' and 'arroz anb …,' similar to 'olla de ….'

In addition, the word olla also exists in Portugal and Tunisia as well as the Spanish-speaking countries as the name of dish (recipe), which means traditional one-pot dish cooked at the table or the pot itself, and today sometimes means a pressure cooker (dish cooked with the pressure cooker).

Another theory is that ojiya was derived from the sound 'jiyajiya,' but it is not supported in recent years.