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Kotonoha Akane & Aoi ((こと)(のは) (あかね)(あおい)) are a pair of vocal synth characters developed by AI, Inc.. They have been released as VOICEROID, Voidol, Synthesizer V, and A.I.VOICE libraries and will be receiving a NEUTRINO Song Library in the Spring of 2022. They are mainly capable of Japanese voice synthesis, however, they have also received English A.I.VOICE voice libraries in December 2021.[1]

Their voice provider is Sakakibara Yui ((さかき)(ばら)ゆい).


The pair are said to be sisters, with Akane being the elder and Aoi the younger. Because she lived in Kansai for a long time, Akane is used to speaking in the Kansai-ben dialect.

Their birthday is April 25, the same day they originally released.


Kotonoha (琴葉) is derived from the words koto (, 13-string Japanese zither), no (, Japanese possessive particle that in classical Japanese was often omitted in writing, especially when writing down full names of people from important clans) and ha (, leaf, plane, lobe, [pine] needle, blade [of grass], spear, fragment, piece); literally, it can be translated to either "leaf of a koto" (if using the most common definition of 葉) or "fragment or piece of a koto". Thus, both Akane and Aoi can be considered to be two fragments of a metaphorical koto which when joined together complete the instrument (or, in this case, the voice library).

Akane () refers to both Rubia argyi (Japanese madder, an east Asian flowering plant) and the red dye that is extracted from such flower. Aoi () refers to a hollyhock flower like the one incorporated into the Tokugawa shogunate's official seal or mon (which was officially called 丸に三つ葉葵 Maruni Mitsuba Aoi); it also shares furigana with aoi (青い, "blue").



Akane is described by her sister as a "natural airhead." While Aoi has a gentle personality, but is more firm than her older sister.[2][3] On the English webpage created to promote their upcoming English voicebanks, Akane is described as "outgoing and cheerful" while Aoi is "calm and reliable".[4]


On November 16th, 2020, A.I.VOICE was announced with the twins confirmed to be one of its first vocals as part of its release in February 2021, along with Iori Yuzuru.[5]

On November 4, 2021, the pair were announced to be receiving English voicebanks for the A.I.VOICE engine.[1] The will be the first English voicebanks released for the software.


On June 30, 2020, AH-Software Co. Ltd. held a Twitter campaign in which users were able to apply by DM to receive a set of Synthesizer V Studio Pro, Synthesizer V Kotonoha Akane & Aoi, and Synthesizer V Saki packaged versions. Ten users were ultimately selected.[6]

Merchandise featuring the Kotonoha sisters' Synthesizer V designs were distributed on the official Kotonoha Akane & Aoi BOOTH account.[7][8] Merchandise included an embroidered polo shirt with the Kotonoha logo and a 15-inch PC case.[9][10]

Kotonoha Rock Fes 2021 Promo.jpg

On February 27, 2021, Akane & Aoi appeared at a live concert performance titled Kotonoha Rock Fes 2021 (コトノハロックフェス2021) held by i-Pairs Inc. in celebration of the release of their Synthesizer V library.[11][12] The sisters performed live on stage as a projection on a screen with a live band performing various original and cover songs.[13]. The event started as a crowdfund with a goal of raising 3,400,000 yen.[14] Over 4,183,444 yen would eventually be raised prompting for the creation of exclusive MikuMikuDance models of the girls' Synthesizer V costumes.[15][16][17]

Akane & Aoi won the Grand Prix Music Category Award for the "35th Vector Pro-Registry Award" on Vector PC Shop[18]


Kotonoha Akane & Aoi
Both of the girls have soft, cute-sounding voices. Akane's voice is made for Kansai-ben intonation while Aoi's has standard intonation. Despite being part of the VOICEROID+ series, they share the same features as those in the VOICEROID+ EX series.
  • Kotonoha Akane & Aoi (VOICEROID+), April 25, 2014
  • Kotonoha Akane & Aoi (VOICEROID2), June 9, 2017
  • Kotonoha Akane & Aoi (Synthesizer V Studio), July 30, 2020
  • Kotonoha Akane & Aoi (A.I.VOICE), February 22, 2021
  • Kotonoha Akane & Aoi Tsubomi (A.I.VOICE), February 22, 2021
  • Kotonoha Akane & Aoi (Voidol), October 12, 2021
  • Kotonoha Akane & Aoi English (A.I.VOICE), December 10, 2021
  • Kotonoha Akane & Aoi Song Library (NEUTRINO), April 25, 2022



  • First and only dual pair VOICEROIDs released.
  • First AI, Inc. VOICEROIDs released.
  • First female VOICEROID (Akane) established to speak Kansai-ben.
  • First VOICEROID characters to have Synthesizer V voicebanks.
  • One of the first Synthesizer V Studio voicebanks released.
  • One of the first female Synthesizer V Studio voicebanks released.
  • One of the first Japanese Synthesizer V Studio voicebanks released.
  • First Synthesizer V voicebank to be developed by AH-Software.


External links[]



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