黒: At the times of 長次郎(ちょうじろう)it was brown black, only when firing temperatures rose later they became fully black.
Ullrich writes that 利休 used 赤楽 for the 2 畳 room, which was already dark, the wands being blackened and all, and using 黒楽 would've been too much. He used 黒楽 in the 4.5 畳 room.
3 colours of 侘び: the green of the 畳, the red of the 茶碗 and the black of the walls of 待庵.
長次郎(ちょうじろう) Ware
1580 mention of red 楽, seems to be the earlier type.
1586 first time mention of a Soeki-shape 茶碗.
Possibly a whole bunch of different potters in the family made pots under this name (CG56).
瞬間(しゅん かん)is possibly by a son of 長次郎(ちょうじろう), seeing how different it is. It is tapered at the lip, and slightly asymmetric. 瞬間 means the time between blinking.
Jokei (II)
It is said that 利休 liked 長次郎(ちょうじろう)'s wares, and his son, Doan, Jokei's.
Nonko (III)
Up to then, the 黒楽 had a “dried” glaze and a brown-black colour.
了入
了入(りょうにゅ)IX (1756-1834) was very prolific, invented cutting method (link), regarded as one of the greatest.