Japanese pottery (yakimono, 焼き物 – not to be confused with yakimono ryori, 焼き物料理 which stands for "grilled food") is an umbrella name used to address any pottery made in Japan. The naming comes from the words yaku (焼く, to burn) and mono (物, object), roughly meaning "burnt thing".
Another common word is tōki (陶器). Although the two are used interchangeably even by Japanese people, they have slightly different meanings.
The word yakimono is used to indicate mainly 3 types of Japanese pottery: tōki (陶器, rendered in English as "ceramics"), jiki (磁器, "porcelain") and sekki (炻器, "stoneware").
Tōki (陶器) Made with clay in a kiln at temperatures between 1000 and 1300ºC. Often finished with glaze due to its tendency to absorb moisture. It is also referred to as doki (土器, "earthenware") when fired at lower temperatures.
Jiki (磁器) Made using silica stone, feldspars, or other rocks that have glass-like properties. The kiln is set at temperatures above 1300ºC.
Sekki (炻器) Made using types of clay that are naturally high in iron, fired at temperatures between 1100 and 1300ºC. It can be vitreous or semi-vitreous, which can result in opalescence.
In some cases, such as with Bizen yaki, it is characterized by its rough looks and touch.
Being nonporous (does not absorb moisture), it does not require glaze finishing.
Types of Japanese pottery
There are several sub-categories of yakimono in Japan, with most of them sporting particular decorations, colors, textures or techniques. This article shows the most common ones in alphabetical order.
The description refers to the traditional local style, while also mentioning a few subtypes of pottery or famous local families (brands.) Some potters adopt approaches that differ from the most popular local style mentioned here, but that does not affect the authenticity of their works.
Arita yaki (有田焼)
Origin: Saga prefecture (Kyushu)
Type: Jiki
Description: Arita ware is usually thin, light and smooth to the touch. Despite that, local potters take pride in the high resistance of their works, obtained thanks to the particularly strong clay used.
The clay is also very white, which allows to paint in very delicate colors.

Banko yaki (萬古焼)
Origin: Mie prefecture
Type: Sekki
Description: The most prominent characteristic in Banko yaki is its high-resistance clay, which allows it to be placed in direct contact with fire. This makes it the favored type of pottery to produce nabe, the terracotta pot used to prepare the omonymous dish.

Bizen yaki (備前焼)
Origin: Okayama prefecture
Type: Sekki
Description: This type of ware is characterized by a brown-red color, and its rough texture caused by the absence of enamel and any other finishing. Similar to terracotta, it is made using a very strong type of clay.Bizen ware is made using high-capacity kilns (often tunnel kilns). This causes each piece of earthenware to be fired differently depending on where it will be hit by the flames, naturally creating a virtually infinite variety of patterns. Firing sessions (production lottos) usually last up to two weeks, over which a large number of products is made. It is one of the six types of pottery called the Six Ancient Kilns of Japan (日本六古窯, Nihon rokkoyō), a small group of types of pottery that are considered the most noteworthy in the history of Japan.

Echizen yaki (越前焼)
Origin: Fukui prefecture
Type: Sekki
Description: Echizen yaki is made using a type of clay rich in iron, which makes it highly resistant to shock, hits and high temperatures. It is fired for relatively longer times, which creates a sort of natural glazing.It is one of the six types of pottery called the Six Ancient Kilns of Japan (日本六古窯, Nihon rokkoyō), a small group of types of pottery that are considered the most noteworthy in the history of Japan.

Hagi yaki (萩焼)
Origin: Yamaguchi prefecture
Type: Tōki
Description: Characterized by soft shapes and colors, and by the particular glaze used, on which distinctive fine cracks (called kannyū) form when dried.

Hasami yaki (波佐見焼)
Origin: Nagasaki prefecture (Kyushu)
Type: Jiki
Description: Hasami yaki is one of the most neutral and versatile types of Japanese pottery. Historically, it is made only using white clay and decorated using indigo-blue paint. However, thanks to its lack of unique traits, many potters belonging to the Hasami school experiment with shapes and colors, often resulting in modern-looking ware that does not resemble the traditional Japanese pottery.

Karatsu yaki (唐津焼)
Origin: Saga prefecture (Kyushu)
Type: Tōki
Description: Characterized by a very simple style, Karatsu yaki positions itself between Raku yaki and Hagi yaki, including rough-looking materials and shapes (as seen in Raku gaki), as well as fine ceramics that still have a rough feel to them (as in Hagi yaki). It was one of the most preferred styles among tea masters, thanks to its simplicity and hand-made looks.

Kyō yaki (京焼) or Kiyomizu yaki (清水焼)
Origin: Kyoto prefecture
Type: Jiki
Description: read the article dedicated to Kyō yaki.
The naming of "Kyō yaki" includes more specific types of pottery, such as Makuzu yaki, Asahi yaki and others.

Koishiwara yaki (小石原焼)
Origin: Fukuoka prefecture (Kyushu)
Type: Tōki
Description: Koishiwara ware is different from most other styles in its wide variety of decorations, which include stripes and other shapes made in the clay (tobikanna, 飛び鉋; hakeme, 刷毛目; and yubigaki, 指描き) or painted on the object after firing (kakenagashi, 掛け流し and uchikake, 打ち掛け, where paint is let slide downards or splashed, respectively), or paint applied directly from its vessel (pongaki, ぽん描き). Koishiwara yaki includes more specific types of pottery, such as Takatori yaki.

Kutani yaki (九谷焼)
Origin: Hokuriku region, now Ishikawa prefecture
Type: Jiki
Description: Traditional Kutani-yaki ware is particularly thick. The design is characterized by black or dark-colored outlines that recall the manga style. This peculiarity makes it the favorite style chosen for character-themed ware. The 5 colors used in the traditional style (red, yellow, green, purple and deep blue) are usually very strong.
Aokutani (青九谷, also Kutani Aote, 九谷青手, in which the red color is not used) and Akakutani (赤九谷, also Kutani akae, 九谷赤絵, characterized by completely red decorations) are two peculiar subtypes of Kutani yaki.

Mashiko yaki (益子焼)
Origin: Tochigi prefecture
Type: Tōki
Description: Mashiko ware is usually thick and characterized by a rough look despite being generously enameled.

Mino yaki (美濃焼)
Origin: Gifu prefecture
Type: Tōki, jiki
Description: Mino ware is considered the most humble and neutral style, so much so that its supporters state that "its lack of peculiarities is its peculiarity". Along with Seto yaki, its versatility makes it one of the two most common types of earthen ware in Japan.
Its neutrality, high versatility and lack of strict regulations brought it to be the umbrella name for several styles adopted in Gifu that, combined, currently provide more than half of the total earthenware produced in Japan.
Words frequently associated with the wide range of Mino ware include haiyū (ash glaze), tenmoku (a type of wan bowl), sometsuke (white pottery decorated with cobalt-base paint), akae (white pottery decorated with red paint), seiji (white pottery decorated with blue paint), tetsuyū (iron-based glaze), and several others.

Raku yaki (楽焼)
'Raku yaki' is a term that indicates any pottery made solely by hand, without the use of electric or foot-operated wheels. Very common examples are represented by the type of bowls used in the tea ceremony (chawan, 茶碗), which are shaped only using the potter's palms, resulting in bowls that fit naturally into a person's hands.

Seto yaki (瀬戸焼)
Origin: Aichi prefecture
Type: Tōki, jiki
Description: Similarly to Mino yaki, earthenware from Seto is characterized by its neutrality. The wide range of styles and materials adopted by Seto potters earned it the definition of "the most representative style of Japanese pottery", as it basically includes any type of pottery without limiting itself or belonging to specific schools.
The word setomono (meaning "Seto objects") is sometimes used to address Japanese pottery regardless of their origin.
It is one of the six types of pottery called the Six Ancient Kilns of Japan (日本六古窯, Nihon rokkoyō), a small group of types of pottery that are considered the most noteworthy in the history of Japan.

Shigaraki yaki (信楽焼)
Origin: Shiga prefecture
Type: Sekki
Description: The most easily recognizable characteristic in Shigaraki yaki is its color: natural-looking patterns are obtained through the spread of ashes on the object during the firing process, which burn and leave dark-colored marks. The clay used is high in iron, which igives this type of ware a naturally brown-red color.
It is one of the six types of pottery called the Six Ancient Kilns of Japan (日本六古窯, Nihon rokkoyō), a small group of types of pottery that are considered the most noteworthy in the history of Japan.

Tamba yaki (丹波焼), or Tamba-tachikui yaki (丹波立杭焼)
Origin: Hyogo prefecture
Type: Tōki, sekki
Description: Tamba yaki is a red-brown type of un-glazed pottery. It is fired for relatively longer times, which creates a sort of natural glazing.
It is one of the six types of pottery called the Six Ancient Kilns of Japan (日本六古窯, Nihon rokkoyō), a small group of types of pottery that are considered the most noteworthy in the history of Japan.

Tokoname yaki (常滑焼)
Origin: Aichi prefecture
Type: Sekki
Description: Like most other styles among the Six Ancient Kilns of Japan, Tokoname yaki has rough looks. It had a brown-red color and it features a naturally developed glaze due to the longer firing times.
The most known Tokoname yaki vessel is arguably the red-brown-colored tea pot.
It is one of the six types of pottery called the Six Ancient Kilns of Japan (日本六古窯, Nihon rokkoyō), a small group of types of pottery that are considered the most noteworthy in the history of Japan.

Yachimun (やちむん in hiragana)
Origin: Okinawa
Type: Tōki
Description: Yachimum ware often portraits shapes that can be seen in nature, such as leaves, waves or fishes. Such shapes, contrarily to what sometimes happens with other pottery styles, are easily recognizable. This is a characteristic of the more basic, somewhat pragmatic approach to decoration in Okinawa.

Origin
The art of shaping, firing and decorating clay to produce ceramics or porcelain was introduced from China around the 5th century. It was then developed and adapted to the Japanese customs for over a thousand years, especially favored by the demand for beautiful equipment for the tea ceremony (茶道, sadō).
It is integral part of Japanese culture, customs, and daily life, especially thanks to the wide range of plates and vessels used to prepare and serve Japanese food.
Authenticity
The naming "yakimono" covers any pottery made in Japan regardless of the specific type of clay used, the techniques, shapes, colors and themes. More focus is given to the place of origin of each piece, which makes it fall into one or another type out of the ones listed above and more.
Did you know?
Some styles are widely known, such as Shigaraki yaki, Bizen yaki and Arita yaki. However, as you might have noticed already, most pottery schools cannot be categorized or grouped in one single style. For this reason, the strict subdivision in schools, styles and places of origins is barely useful when it comes to choosing a style over another: most Japanese people could not recognize them, and prefer to choose their earthenware based solely on their looks.