Kyusu Banko
Iroku Maruhari


A jewel of the banko yaki kyusu tradition, this iconic teapot features Master Iroku's signature handcrafted diamond pattern. This style has been perfected over the course of three generations of master craftsmen.
Type Side-handle yokode kyūsu (横手急須)
Kiln Banko yaki (萬古焼)
Studio/Artist Master Iroku
Origin Yokkaichi, Mie, Japan
Capacity 200ml
Recommended filling quantity For optimal serving, it is recommended to fill only up to the last third of the integrated strainer
Dimensions 9.5 x 5.5cm (diameter without handle x height without knob)
Weight 170g
Clay Purple natural clay (shidei; 紫泥)
Firing Reduction firing (還元焼成)
Glaze Unglazed inside and out (yakishime; 焼き締め), polished finish for a beautiful sheen
Pattern Diamond-shaped cuts
Strainer Handmade cylindrical strainer
Finish The components of the lid and jug are hand-potted on the potter's wheel and then assembled to fit exactly (rokuro; 轆轤)
Stamp Artist's stamp
Packaging Signed wooden box (kiribako)

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Iroku Mori 伊呂久

Iroku Mori 伊呂久

The venerable Iroku firing company was founded in 1880 in Yokkaichi in the middle of the Meiji era and is now run by the fourth generation, Iroku Mori, who, like his father, is an award-winning certified traditional craftsman. From the beginning, the ceramic studio has strived to produce novel yet playful-looking Banko Kyusus that are a joy to look at, as well as to use. Iroku has therefore always specialised in decorative techniques, in particular the traditional Matsukawa pine bark pattern applied directly to the spinning kyusu body and the characteristic Daiya diamond cut. This geometric pattern has been perfected over three generations and is cut into the surface by hand. A laborious task of great delicacy: it can take up to half a day to decorate a single kyusu. The brilliance of these diamond-cut masterpieces make them coveted collectors' items absolute jewels of Yokkaichi Banko art.

Banko Kyusu

A kyusu is a traditional Japanese teapot for the ideal preparation of Japanese green tea. Fired from natural clay and unglazed on the inside, the body reacts with the water and the tea and brings out certain aromas. The tea can steep optimally free-floating in the pot; moreover, the leaves lie advantageously over the integrated sieve when poured in, so that on the one hand they filter themselves, on the other hand they allow a more complete extraction of flavours and ingredients. The tea is only ever brewed fresh, but several times. The side handle and the knob on the lid prevent the hand from coming into contact with the excessively hot body.

Throughout history, there have been hundreds of ceramic centres in Japan, wherever the volcanic soil had rich clay deposits. Some are still active today, including the six most important "old kilns" (Rokkoyo): Bizen, Shigaraki, Seto, Echizen, Tamba and Tokoname. But also others such as Karatsu, Hagi, Mino, Shino, Oribe, Setoguro Ki-Seto and Kyo-yaki, and for tea ceramics above all Banko in Yokkaichi.

They differ regionally according to the composition of the clay, the prevalent firing method, the handwork steps, decoration and glazing techniques and the fineness or deliberate coarseness of the production. Above all, the clay and the firing determine the flavourful character of the kyusu, i.e. which types of flavours of a tea are lifted or subdued by it. For this reason, tea lovers often have various Kyusu of different qualities at home, in order to enable the optimal preparation depending on the tea and its quality. Among the finest and most valuable kyusu are those made by famous artists who are renowned not only for their special talents in manufacturing, form and decoration, but also for their own production of the natural clay as well as their own firing techniques that result in unique qualities.

Led by the Living National Treasures, the most highly awarded masters, there is a whole hierarchy of craftsmanship, ranging from studios that still draw on the reputation of past masters, young and wild studios, to family-run micro-enterprises that produce the bulk of everyday ceramics. Important collector's items are the vintage kyusus, which are still made entirely from now exhausted deposits of the highest quality natural clay of the respective region and thus achieve incomparable qualities in tea infusion.

Banko Yaki

Yokkaichi Banko-yaki 四日市萬古焼

The merchant and passionate chajin ("tea man") Nunami Rozan is considered the founding father of banko-yaki. As early as the 18th century, he opened a kiln in what is now Asahi-machi in Mie Prefecture and stamped his wares 萬古不易 banko-fueki: "eternally unchanging" – in the hope that his ceramics would continuously be passed down through generations. Today, banko-yaki is still made in Mie Prefecture, mainly in the city of Yokkaichi, and is considered a protected traditional craft of Japanese culture. Synonymous with banko is the locally typical, ferruginous shidei "purple clay", which becomes extremely heat-resistant when fired in a high-temperature reduction kiln, taking on the characteristic deep purple-brown colour and an almost metallic sheen. It is said that the tannins in the green tea react with the iron in the unglazed Shidei tea ware and soften the astringency of the tea, accentuating its sweetness; therefore, umami-rich teas such as Sencha, Kabusecha and Gyokuro are highly recommended for use with Banko.



Natural, purple clay (shidei 紫泥).


The components of the lid and jug are hand-potted on the potter's wheel and then assembled for a perfect fit (rokuro 轆轤).

Strong Reduction Firing (Kyo-kangen Shosei 強還元焼成)

When firing ceramics, various processes start as the temperature rises. First, the water still left in the body evaporates. Above a temperature of 500°C, the clay is completely dehydrated and its chemical state is irreversible. The organic components burn and oxidation takes place. After solidification, the vitrification phase begins.

Reduction firing of the ceramic produces an excess of carbon and a reduction of oxygen in the kiln. Carbon monoxide extracts oxygen from the surroundings and the body. A strong smoke development is the result. The body changes colour, from light grey to black, depending on the intensity and time of the reduction. The clay has less oxygen, becomes firmer and more solid and at the same time acquires greater porosity. All in all, this leads to the specific properties of a kyusu fired in this way when preparing green tea in terms of taste and effect. After firing, the special clay, which is rich in minerals, reacts in a characteristic way with the ingredients of the tea and the water (see the tab on tea varieties).


Unglazed (yakishime 焼き締め).

Suitable for

Recommended for Use with the Following Japanese Green Teas:

Umami-strong, less bitter green teas
Varieties: Umami-rich Senchas / Shinchas, Gyokuro, Kabusecha, Gyokuro Karigane
Harvest: 1st harvest
Cultivars: Fujimidori, Gokō, Kanayamidori, Komakage, Kuritawase, Okumidori, Saemidori, Samidori, Shojū, Yutakamidori, blends of these cultivars.

Brown / purple earthenware from strong reduction firing (Banko) accentuates the noble softer and sweeter flavours (esp. amino acids) and umami of upscale green tea by activating the iron content and higher porosity. This brings out the strengths of umami-rich teas better. Their taste becomes richer and more persistent.

In the long run, it is advisable to use only the similar tea types recommended above in the same kyusu. The Kyusu made of natural clay develops a patina in interaction with the respective tea, which improves and intensifies the taste over time. For this reason, too, if possible, do not use tap or bottled water with a high lime content, but rather soft, low-lime water (similar to natural mountain spring water).


Please always use low-limestone water for all preparation and cleaning steps of Japanese ceramics.

A kyusu should first be warmed with warm water before the actual tea preparation so that the clay can react better with the tea leaves. Only then are the tea needles put in with a wooden spoon. Depending on taste, variety and quality, 1-3 heaped teaspoons per person are recommended. Advanced connoisseurs usually prepare the tea much stronger than beginners, who are less accustomed to the intense taste and bitter substances.

Now pour the water carefully and slowly over the leaves, ideally from a yuzamashi (vessel for cooling the water after boiling) of the same or similar clay and firing. For better results, fill the water only to the top third of the sieve. Please close the lid during the brewing.

To pour, hold the kyusu with one hand so that the thumb rests on the knob. Make sure that the small opening on the lid is at the same level with the spout. Then pour the tea slowly into the cup in several puffs and drink it fresh. If several cups are being filled, they should be poured in small steps one after the other to achieve an even result for all cups. At the end of the pouring process, carefully but firmly jerk the kyusu downwards repeatedly with both hands to extract the last, particularly rich drops from the tea.

Then leave the kyusu closed for the next infusion. After the last infusion, remove the tea completely from the kyusu and rinse it vigorously with water only. Do not scratch or otherwise clean the inside. Finally, rinse the inside and outside of the pot with low-limestone, soft water in order to avoid detrimental limescale deposits. Briefly rub the outside with a clean cloth, then leave the kyusu open to dry completely.


The Shidei Banko will quickly develop a patina and gain more and more lustre with use. In the first few months it is normal to see fingerprints on the surface, but these will gradually disappear as the surface begins to develop a deep lustre – simply enjoy watching the kyusu transform in your hands! Use only water and a soft cloth to clean it and then allow it to air dry. Do not use detergents and do not put it in the dishwasher. Hard water can cause limescale deposits. In this case, rinse with soft bottled water and wipe with a soft cloth.

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