Ningyo mentioned incense contests in a post elsewhere, and as I�d never heard of this before I decided to look up a bit about them *S*. The first thing I discovered is that the incense contests of the 11^th century are not to be confused with the later Ko-do or Japanese Incense Ceremony, which dates back to the Muromachi period (1336-1573). In the Heian incense contests, participants were judged on their incense making and blending skills, while Ko-do was more of a "guess the incense" type game.

The early Heian period witnessed great cultural exchanges between Japan and China . The Chinese had been using incense for a long time to perfume their home and garments and to accompany the enjoyment of tea and relaxation, and Buddhist monks were well trained in the medicinal properties of incense as well as herbs. As Buddhism became accepted by the Japanese, so increasingly was the use of incense integrated into the everyday and social structures of Japanese society.

During this period, a unique and new form of kneaded incense developed in Japan, called Awaseko or Neriko (香合わせ). In order to compound the mixtures of the Chinese herbalists and Buddhist monks, incense mixtures were blended with plum meat or honey. When left to mature they rendered a warm, enticing, and somewhat sweet aroma that lasted for a longer period. This was the incense used to perfume sleeves and garments. Later it became the winter standard for the Japanese tea ceremony.

In the Heian Period there were six kinds of famous mixed incense:

Baika - Plum Blossom blend, used in spring.
Kurobo - used in all four seasons.
Yoka - used in the summer.
Jiju - used in the winter.
Kikka  chrysanthemum blend, used in autumn
Rakuyo - falling leaf blend, used in mid autumn

Along with neriko, incense contests (Takimono Awase 薫物合わせ) begin to appear, in which the leisured aristocracy would compete against each other to be judged on their incense making skills and the quality of their aromatic blend. Not only the Japanese ladies, customarily trained in these kinds of graces, were making their own incense, but also the gentlemen of the court as well. It quickly became an integrated part of Japanese culture.

These are the incense contests that we find described in Genji Monogatari:

The time had come to review the perfumes. "It should be on a rainy evening," said Genji. "And you shall judge them. Who if not you?" He had censers brought in. A most marvelous display was ranged before the prince, for the ladies were determined that their manufactures be presented to the very best advantage. "I am hardly the one who knows," said the prince. He went over them very carefully, finding this and that delicate flaw, for the finest perfumes are sometimes just a shade too insistent or too bland. Genji sent for the two perfumes of his own compounding. It being in the old court tradition to bury perfumes beside the guardsmen's stream, he had buried them near the stream that flowed between the main hall and the west wing. He dispatched Koremitsu's son, now a councillor, to dig them up. Yu~giri brought them in. "You have assigned me a most difficult task," said the prince. "I fear that my judgment may be a bit smoky." The same tradition had in several fashions made its way down to the several contestants. Each had added ingeniously original touches. The prince was faced with many interesting and delicate problems. Despite Asagao's self-deprecatory poem, her "dark" winter incense was judged the best, somehow gentler and yet deeper than the others. The prince decided that among the autumn scents, the "chamberlain's per- fumes," as they are called, Genji's had an intimacy which however did not insist upon itself. Of Murasaki's three, the plum or spring perfume was especially bright and original, with a tartness that was rather daring. "Nothing goes better with a spring breeze than a plum blossom," said the prince. Observing the competition from her summer quarter, the lady of the orange blossoms was characteristically reticent, as inconspicuous as a wisp of smoke from a censer. She finally submitted a single perfume, a summer lotus-leaf blend with a pungency that was gentle but firm. In the winter quarter the Akashi lady had as little confidence that she could hold her own in such competition. She finally submitted a "hundred pace" sachet from an adaptation of Minamoto Kintada's formula by the earlier Suzaku emperor, of very great delicacy and refinement. The prince announced that each of the perfumes was obviously the result of careful thought and that each had much to recommend it.
- From The Umegae Chapter (A Branch of Plum) in "Genji Monogatari"

In the Genji tale, the contests were judged on the creation and art of incense making, but sometime after the Heian period the attention focused more on guessing games of identification. Informal games called Koh Awase were played in Japanese homes, and it was from these games that the later Ko-do, or "Incense Ceremony" takes its true origination.

Sourced from:
http://www.oller.net/
http://www.japanese-incense.com