On Kaki-Shibu, a Fruit Juice in Technical 

 Application in Japan, 



BY 



M. Tsukamoto. 



The name " Kaki-shibu," or more briefly " Shibu," is given 

 in Japan to the juice of the unripe fruit of the Kaki tree 

 (Diospyros Kaki, L.). This juice serves for the preservation of 

 fish-nets and fish-lines which are soaked in the liquid and left to 

 dry well in the sun. After this treatment the nets or lines are 

 much more durable. It further serves as an application to 

 packing papers, 1 especially such as are used for packing tea. 

 Since such paper is less penetrable by moisture, the danger of 

 mould development in the tea in warm and moist climates is 

 diminished. Also tubs and other wooden vessels are treated 

 with the juice to render them more durable. Further the juice is 

 frequently mixed with India ink and the mixture is then used as 

 a paint for the outer walls of wooden buildings and also for 

 wooden fences. 



Considering that the Kaki-shibu has such important techni- 

 cal applications it appeared desirable to subject the juice to 

 an investigation. First of all it should be stated that not every 

 kind of Kaki fruit yields suitable juice. There are found two 

 varieties of the Kaki in Japan : one becomes very sweet when 

 ripened, while the other remains astringent and is very rich in 

 tannin, 2 yielding in great quantity the juice desirable for making 

 Kaki-shibu. Such fruit when full grown is only 3-4 cm. in 

 diameter. 1200 kg. of the fresh fruit when well crushed 

 and mixed with about 2 hi. of water will yield nearly 7 hi. 

 of Kaki-shibu. The mixture remains three or four days in 



* Also other kinds of paper are thus treated and used for various household and 

 commercial purposes. 



2 In order to make the fruit of some of this variety palatable, it is necessary either 

 to treat it when well-ripened with a very diluted lye, or to dry it in the sun after taking 

 off the skin. 



