重茶碗（かさね ちゃわん）
When there are more than five guests for 濃茶（こいちゃ）, host enters with stacked 茶碗. The one in the inside, holding 茶巾, 茶筅 and 茶杓 is called 主茶碗（おもじゃわん）, and is used for the first guest. The outside one is called 替茶碗（かえじゃわん）, which means alternate bowl.
According to Chanoyu Vocabulary, different kinds of ceramic should be used here; unless it's 島台（しまだい） 茶碗. Alt least one should be 楽, so you can avoid having to carry two 古帛紗.
点前
- move 茶碗 stack with 2 hands
- first tea is only scooped, no cleaning of the 茶入 rim
- when first guest picks up bowl, bow and tell them how many people it's for (〇〇様ごしょ)
- still, bow with everyone
- after first guest's first sip, take out second bowl
- this time, place 茶巾 on 釜豚
- again, ask about the tea, then open 水指 and add cold water
- both bowls are inspected, and returned by the main guest
- finish (中) with first bowl, but don't move 建水. Guest may ask about 茶碗 after it was rinsed
- then second bowl is returned, rinse and rotate twice, then move 建水
- close 水指, receive 拝見 request, move 主茶碗 into second 茶碗; prepare 拝見