After learning the procedure for drinking usucha (thin tea) and then for preparing it, in other words, after the etiquette of tea procedure has been learned, at last there is practice for preparing koicha(thick tea), thickly mixed tea, in a bowl from which a number of people will drink. This is several times as thick as usucha and about as thick as kuzuyu (arrowroot starch gruel). It takes a considerable degree of skill to achieve the right thick but smooth consistency, and the knowledge of the utensils that are used should also become deeper along with that of temae etiquette.
After two or three years of practice when you have become quite good at thin tea and thick tea procedures, you will at last want to invite close friends and try entertaining them and conducting yourself as a host. In other words, you want to try hosting a tea event and entertaining guests.
For this you will need to boil water in a kettle in a tea room and to have a set of utensils for tea preparation.

First there is the simplest kind of tea gathering with just a bowl of thin tea served. Then there is the simplest kind of food served with thin tea. Finally there is the 'formal tea event', namely the 'chaji', at which thick tea and thin tea are served with 'formal chanoyu cuisine' (kaiseki). This is the most polite form of entertaining through chanoyu. Mastery of this 'chaji' is the highest aim of keiko (practice). So the aim of chanoyu's practice is to entertain guests at tea gatherings and tea events.
As preparation for a tea event, it will be necessary to clean the tea garden and the tea room, and to carefully select a set of utensils for tea procedure and a set of vessels on which to place the food. Having a set of kaiseki-dogu (vessels for kaiseki cuisine) is also recommended.