To make Gyokuro, a black cloth cover is put on top of the tea leaves
 20 days before the tea plucking, which will suppress the
 creation of tannin and hence contains more theanine, which are
 the sources of good taste. To enjoy real taste of Gyokuro
 you will first put gyokuro into the tea pot, and pour hot water in tea-cup
 then pour back the cooled down-warm water into the teapot, and then serve
 back into the teacup again.
 Taste of tea is best if the color is pure green or pure yellow.