In kōdō, a small piece of fragrant wood is heated on a small Mica plate (Gin-yo), which is heated from below by a piece of charcoal that is surrounded by ash. All this is held in a small ceramic censer that can look like a cup. It is not usual for wood or incense sticks to be burned because that would create smoke; only the essential aromatic oils should be released from the wood through the heat below it.
Aloeswood, also known as agarwood (沈香 jinkō), is produced in certain parts of southeast Asia such as Vietnam. The trees secrete an aromatic resin, which over time then turns into kōboku (香木). One particular grade of kōboku with a high oil content and superior fragrance is called kyara (伽羅).
Another important material is sandalwood (白檀 byakudan), which originates primarily from India, Indonesia, southern China or other parts of southeast Asia. Sandalwood trees need around 60 years to produce their signature fragrance that can be deemed acceptable to be used for kōdo.
Other materials used are cinnamon bark (桂皮 keihi), chebulic myrobalan (诃子 kashi), clove (丁子 choji), ginger lily (sanna), lavender, licorice (甘草属 kanzō), patchouli (廣藿香 kakkō), spikenard (匙葉甘鬆 kansho), camomile, rhubarb (大黄 daioh), safflower (紅花 benibana), star anise (大茴香 dai uikyo) and other herbs. Shell fragrances (貝香 kaikō) and other animal-derived aromatic materials are also used.