Akatsuki Ring Trivia
Right thumb: 零 (rei, "zero"); worn by Pain,
Right index finger: 青 (sei, shō, "blue," "green"); worn by Deidara.
Right middle finger: 白 (bya, "white"); worn by Konan.
Right ring finger: 朱 (shu, "vermilion," "scarlet"); worn by Itachi Uchiha.
Right little finger: 亥 (gai, "sign of the boar"); worn by Zetsu,
Left little finger: 空 (kū, "sky," "void"); worn by Orochimaru.
Left ring finger: 南 (nan, "south"); worn by Kisame Hoshigaki.
Left middle finger: 北 (hoku, "north"); worn by Kakuzu.
Left index finger: 三 (san, "three"); worn by Hidan.
Left thumb: 玉 (gyoku, "jewel," "ball," also the black king in shogi); worn by Sasori and later by Tobi.
Their ring placement on their finger corresponds to their position on the summoned statue, with each member wearing the ring on a different finger. The rings seem important to each member, as Deidara was set on finding his when it was lost. Orochimaru also took his when he left the group, which apparently denied the group the ability to replace him with someone new. With Sasori's death, Tobi was eager to get his ring and join, but he would need to go through their entrance requirements first.