Each member of Akatsuki was assigned to stand on a specific finger of the Gedo Statue, which correlates with the same finger they are wearing their ring.
Each member would stand on their designated Gedo Statue finger and focus their Chakra into the statue to seal the tailed beast one by one.
In the process, the different Kanji on their ring would appear on the finger of the statue, indicating the sealing is in progress.
Purpose of the Ring
There is also a theory that these rings were made by Nagato himself, so by receiving and emitting the chakra he was able to communicate with Members of the Akatsuki.
This also allowed him to keep tabs on members. The Key also allowed the members to astroproject themselves in the meeting.
Here is a list of all the Akatsuki rings and their owners, where we explained what does each Akatsuki ring means and in which finger you should wear them.
Itachi‘s ring is red with Japanese Kanji 朱 (“Shu”), which means “crimson”. This ring must be worn on the right ring finger.
Kisame‘s ring is yellow with Japanese kanji 南(“Nan”), which means the “South”. The right place to wear his Akatsuki ring is on the left ring finger.
Konan‘s ring is white with Japanese Kanji 白(“Byaku”), which means “white”. Konan’s Akatsuki ring must be worn on the right middle finger.
Pain‘s Akatsuki ring is blue or yellow with the Japanese Kanji 零 (“Rei”), which means “zero”. Pain wears his ring on the right thumb and his kanji is unrelated to Chinese Gods.
Orochimaru‘s ring is red with Japanese Kanji 空 (“Ku”), which means “Sky” and “Void”. Orochimaru‘s(one of the legendary sannin) Akatsuki ring must be worn on the left little finger.
Deidara‘s ring is blue with Japanese Kanji and 青 (“Sho”), which means “Blue”. The right place to wear his Akatsuki ring is the right index finger.
Hidan‘s ring is green with Japanese Kanji 三(“San”), which means “Three”. Hidan’s Akatsuki ring must be worn on the left index finger.4
Zetsu‘s ring is Yellow or Red with Japanese Kanji 亥 (“Gai”), which means “Boar”. Zetsu’s Akatsuki ring must be worn on the right little finger.
kakuzu‘s ring is Blue with Japanese Kanji 北(“Hoku”), which means “North”. kakuzu’s Akatsuki ring must be worn on the left middle finger.