How to Care for Japanese Porcelain: Kutani, Koransha and Mino-yaki
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Japanese porcelain is designed to last for decades. But that longevity depends on how you care for it — and not all Japanese ceramics are cared for in the same way. This guide explains what matters: which pieces can go in the dishwasher, which require hand-washing, and why, with specific guidance for Kutani, Koransha and Mino-yaki.
The One Rule That Governs Everything
Before any other guidance: the key variable is not whether a piece is Japanese, or how expensive it was, or which kiln produced it. The key variable is where the decoration sits relative to the glaze.
There are two fundamental decoration types in Japanese porcelain:
1. Underglaze decoration
Pigments applied to the unfired clay body, then covered with a transparent glaze and fired at high temperature (typically 1,250–1,300°C). The decoration is physically sealed beneath the glaze. It cannot flake, fade or be scratched away. Koransha's cobalt patterns and most Mino-yaki glazes are underglaze.
2. Overglaze decoration
Pigments applied after the first glaze firing, on top of the glazed surface, then fired again at lower temperature (700–900°C). The decoration sits above the protective glaze. It is more susceptible to alkaline detergents and mechanical abrasion. Most Kutani hand-painting is overglaze work.
This distinction — overglaze versus underglaze — is the most reliable indicator of how a piece should be washed. It explains why Koransha's fine-looking cobalt patterns are actually quite durable, and why Kutani's bold hand-painting requires more attention.
Quick Reference: Dishwasher, Microwave and Oven
| Piece type | Dishwasher | Microwave | Oven |
|---|---|---|---|
| Kutani — hand-painted overglaze, no gold | Hand-wash only | Check listing | No |
| Kutani — with gold or metallic overglaze | Hand-wash only | No | No |
| Koransha — cobalt underglaze, no gold | Gentle cycle | Yes | No |
| Koransha — with gold accent work | Hand-wash only | No | No |
| Mino-yaki — glazed, no metallic decoration | Yes | Yes | No |
| Mino-yaki — with metallic or overglaze decoration | Check listing | No | No |
When in doubt, check the individual product listing or contact us. We specify care requirements for every piece in our catalogue.
How to Hand-Wash Japanese Porcelain
Hand-washing is always the safest method for fine Japanese ceramics, regardless of the glaze type. If you are unsure about a piece, hand-wash it. Here is how to do it correctly.
1. Wash immediately after use
Do not let food residue dry on the surface, particularly anything acidic (citrus, tomato, vinegar-based dressings). Acids can affect glaze stability over time, especially on pieces with older or thinner glaze surfaces. Rinse with warm water as soon as possible after the meal.
2. Use warm water and mild detergent only
Avoid strongly alkaline or abrasive detergents. A small amount of mild washing-up liquid applied with a soft cloth or non-abrasive sponge is sufficient. Never use steel wool, abrasive pads or scouring powder on Japanese porcelain — even on plain-glazed pieces, these will dull the glaze surface over time.
3. Handle the foot rim with care
The foot rim — the unglazed ring on the base of a piece — is often left unglazed intentionally, as a mark of the kiln tradition. It is porous and can absorb moisture or staining agents. Avoid soaking pieces that have an unglazed foot. Dry the foot rim promptly after washing.
4. Dry immediately — do not let pieces air-dry wet in a rack
Standing moisture at the foot rim is the most common cause of damage to Japanese ceramics in everyday use. After washing, dry the piece with a soft cloth immediately. If you use a drying rack, position pieces so the foot rim is not resting in pooled water.
Using a Dishwasher: When It's Acceptable and How to Do It Right
For Mino-yaki and underglaze Koransha pieces without metallic accents, a dishwasher is a reasonable choice for daily use. The key is to mitigate the three main risks: mechanical abrasion from pieces knocking together, thermal shock from aggressive heat cycles, and chemical damage from harsh detergents.
1. Load with space between pieces
The most common cause of chipping and cracking in a dishwasher is pieces knocking against each other during the wash cycle. Load Japanese ceramics with enough space so nothing can contact anything else, even during the spray arm rotation. The top rack is preferable.
2. Select a gentle or china cycle
High-temperature cycles and intensive programmes are the second most common cause of glaze damage. Use the gentlest setting available. Most modern dishwashers have a "china" or "delicate" programme — use it.
3. Use a mild, phosphate-free detergent
Strongly alkaline detergents attack glaze surfaces over time, causing a progressive dulling that is irreversible. Choose a mild, phosphate-free dishwasher detergent. If you notice your glazes becoming less bright after repeated machine washing, the detergent is usually the cause.
4. Disable heat-dry; air-dry instead
The heat-dry phase of a dishwasher cycle creates thermal stress as pieces cool rapidly from a high temperature. Open the dishwasher door at the end of the wash cycle and allow pieces to air-dry at room temperature. This single change will significantly extend the life of glazed surfaces.
Microwave Use
The rule here is simple: no metallic decoration in a microwave, ever. This applies to gold, silver, platinum and any other metallic overglaze accent — whether on Kutani, Koransha or any other piece.
Metallic decoration in a microwave will arc. The arc damages the metallic glaze irreversibly, and it risks damaging the microwave itself. Even a piece with a very small amount of metallic decoration — a gold rim, a thin gilded line — should not go in a microwave.
For plain-glazed Mino-yaki and underglaze Koransha without metallic accents, microwave use is generally safe. We specify this per piece in our product listings. If the listing does not mention microwave safety, treat the piece as microwave-unsafe until you contact us to confirm.
Storage: The Most Overlooked Part of Care
Most damage to Japanese ceramics happens not during use but during storage. Stacking pieces without protection is the single most common source of glaze scratching and chipping.
1. Never stack without padding
The foot rim of a Japanese ceramic piece is often unglazed — which means it is abrasive. When stacked directly on top of another piece, it will scratch the glaze of the piece beneath it. This damage is gradual and cumulative. Use soft felt pads, cloth napkins or purpose-made ceramic separators between every stacked piece.
2. Store in a dry location, away from direct sunlight
Prolonged exposure to direct sunlight can affect some overglaze pigments over years of storage. More practically, humidity fluctuations in storage — common in UAE homes with strong air conditioning — can cause micro-cracking in the glaze of porous ceramic bodies. Store Japanese ceramics in a consistently dry environment.
3. Consider using pieces rather than storing them
Japanese ceramics are designed to be used, not stored. A piece that is in regular use — washed, dried, placed on a table — is far less likely to be damaged than one kept in a cabinet. If you find yourself storing pieces because you are worried about damaging them, the pieces are not serving their purpose.
Care by Tradition: Specific Notes
Kutani
All Kutani pieces with hand-painted overglaze decoration — which is most of them — should be hand-washed. This is not negotiable. The overglaze pigments are fired at lower temperatures than the base glaze and sit above the protective surface. Repeated dishwasher cycles will cause the colours to fade and the decoration to lose its depth within months.
Pieces with gold or metallic overglaze — including the kinrande (gold brocade) style — must never go near a microwave. Hand-wash only, dry immediately, and keep away from strongly acidic foods (vinegar, citrus juice) for extended periods.
Kutani is worth the extra care. The decoration on a well-maintained Kutani piece looks as vivid after fifty years of use as it did on the day it was made.
Koransha
The cobalt underglaze decoration on most Koransha pieces is sealed beneath the final high-temperature glaze and is quite robust. Pieces without metallic overglaze accents can be machine-washed on a gentle cycle. Use a mild detergent and disable the heat-dry function.
Koransha pieces with gold rim work or overglaze accents — which many of the more elaborate pieces carry — revert to the same rules as Kutani: hand-wash only, no microwave.
The white of Koransha's porcelain body is a key part of its aesthetic. To keep it bright, avoid strongly coloured foods resting on the surface for extended periods — particularly turmeric, berry-based sauces and red wine.
Mino-yaki
Mino-yaki is the most forgiving of the three traditions. The dense clay body and natural ash, iron and celadon glazes are designed for daily use and tolerate machine washing well. Most pieces in the Paean catalogue are dishwasher and microwave safe — check individual product listings for the specifics.
Shino-style Mino-yaki — with its thick, white glaze and characteristic tiny surface bubbles — can be an exception. The textured glaze surface can trap food residue and may be better maintained with hand-washing to preserve the surface character.
Removing Stains
Tea and coffee staining is common on white porcelain and light-glazed ceramics in regular use. For plain white or light-glazed Mino-yaki and Koransha, a diluted solution of white vinegar and water (equal parts) applied with a soft cloth will remove most light staining without damaging the glaze.
Do not use bleach on any Japanese ceramic with painted decoration — overglaze or underglaze. Bleach will attack the pigments and cause irreversible discolouration. For more stubborn stains on plain-glazed pieces, a small amount of baking soda mixed with water to form a paste, applied gently with a soft cloth, is a safer alternative.
For Kutani pieces with staining in recessed areas of the decoration, the safest approach is to soak briefly in warm (not hot) water and use a soft artist's brush to work the stain free. Do not use any chemical cleaning agents on the painted surface.
If you have a question about a specific piece or a specific staining issue, contact us. We would rather answer a question than have a piece damaged.