Chakai A chakai is usually a rather public event. Commonly held at temple in connections to kenchashiki (offering of tea to the Gods). But there are many other events for which a chakai may be held, some example could be: hatsugama (first tea of the year), robiraki (opening of the hearth), memorial service and so forth.
One of the main distinguishing feature of a chakai is that the host does not necessarily know all the guests personally. One seki, seating may include as much as 50 guests. So it goes without saying that they all can not be made tea individually by a single host. So what is done instead is that usually the first two or three guest is served from the temae za by the host. The rest will be served tatedashi, meaning that assistants of the host carry out already whisked tea and present it to the various other guests.
This way a lot of guests can be served tea in the time it takes the host to make two or three bowls of tea.
For chakai one would normally buy a ticket, for the event. This might or might not cover the expenses of the host. Some guests might bring a mizuya mimai for the host when they arrive at the chakai. This is usually sweets, money or something else that can easily be divided or consumed by the host and the assistants.