Blue rice cake

Japanese: 青黐 - あおもち

...A sticky rubber-like substance found mainly in the bark of plants of the Ilex genus of the Ilex family. In Japan, it has long been used as an adhesive. The main component is waxy and called mochi wax, with a few percent of other resins and rubber. Mochi wax is a higher alcohol ester of palmitic acid C ₁₆ H ₃₂ O ₂ , and the alcohols are motil alcohol C ₂₈ H ₄₆ O, irisyl alcohol C ₂₂ H ₃₅ O, and trochole C ₂₆ H ₄₄ O _2. It also contains esters of trochosterin, trochoic acid, cerotic acid, and oleic acid. ...

From [Ilex]

...In spring and summer, the bark is peeled off, soaked in water to rot, and then pounded in a mortar to obtain a rubbery substance. Most species of Ilex (English name: holly) contain this ingredient, but the one from Ilex is called honmochi, and is distinguished from the blue mochi from holly and boxwood. Wakayama, Mie, and Nara prefectures are the main production areas. ...

*Some of the terminology explanations that mention "Seiki" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…おもにモチノキ科モチノキ属植物の樹皮に含まれる粘着性ゴム状物質。日本では古くから粘着剤として用いられた。主成分は蠟質でもち蠟といい，ほかに樹脂，ゴムを数％含有する。もち蠟はパルミチン酸C₁₆H₃₂O₂などの高級アルコールエステルで，アルコールはモチルアルコールC₂₈H₄₆O，イリシールアルコールC₂₂H₃₅O，トロコールC₂₆H₄₄O₂などである。そのほかトロコステリン，トロコ酸，セロチン酸，オレイン酸のエステルなども含む。…