Hajime Nakamura
 
The term wagashi, for confectionary made using methods traditional to Japan, was coined after the introduction of european culinary traditions in the mid nineteenth century. It has become a term that also includes the japanese pastry brought to Japan by its envoys to China (Karagashi) and those later introduced by the Spanish and Portuguese (Nanbangashi). 
The sugar-based wagashi served in the tea ceremony, with both thin and thick tea (usucha and koicha) are as beautiful as they are delicious. Moist sweets are usually served with thick tea and dry sweets with thin tea.
Because they're served with tea, these wagashi  are often quite sweet and are made with almost no oil. The short list of ingredients includes sugar, mizuame (a sweetener made by converting rice or sweet potato starch to syrup), rice, wheat flour and azuki beans. Poached or dried fruit is also used but almost no fresh fruit.  
The use of sugar as a wagashi ingredient dates from the early modern period. In particular, in the Edo period, when white sugar was hard to come by, refined japanese sugar (wasanbon) with its distinctive flavour and nicely balanced sweetness, contributed to dramatic advances in wagashi. Given that the sweetest treats, before sugar became available, were persimmons, it's possible to imagine the delicacy of the sweetness of wagashi. These confections were required to be as delightful to look at as they were delicious. The ingredients were also chosen to be seasonally appropriate. In the summer, for example, wagashi might be given a translucent coating, to communicate a refreshing sense of coolness. In confectionary raised to the level of an art form, these edible delights expressed the wonders of nature.
Wagashi can be broadly grouped into three types according to moisture content. Those with a moisture content of 20% or less are referred to as dry sweets (higashi); those with 40% or more are moist sweets (namagashi), and those in between are semi-moist (han namagashi).