Dai Gyakuten Saiban: Naruhodō Ryūnosuke no Bōken

Unreleased
 * This article is about the game. You may be looking for the character Ryūnosuke Naruhodō.

Dai Gyakuten Saiban: Naruhodō Ryūnosuke no Bōken (大逆転裁判 -成歩堂龍ノ介の冒險-; lit. "Grand Turnabout Trial: The Adventures of Ryūnosuke Naruhodō") is an upcoming Ace Attorney prequel game for the Nintendo 3DS, published by Capcom, directed by Shu Takumi, and produced by Shintaro Kojima, with art by Kazuya Nuri. It is the ninth title overall in the Ace Attorney series of text adventure video games. Unlike previous canonical games in the series, which were set in the near future and featured somewhat futuristic technology, Dai Gyakuten Saiban will be set near the end of Japan's Meiji period. The game will star Phoenix Wright's ancestor Ryūnosuke Naruhodō, and a female judicial assistant named Susato Mikotoba. Although the game initially takes place in Japan, Naruhodō and Mikotoba will later travel to England and encounter the renowned detective Sherlock Holmes.

Main characters

 * Ryūnosuke Naruhodō (成歩堂 龍ノ介) - A second-year university student who gets caught up in an incident and finds himself on the defense's bench three days later. He has a strong sense of justice and is quick to put himself in danger. At the time in which the game takes place, the profession of "defense attorney" is still a fairly new concept in Japanese society. An ancestor to Ryūichi Naruhodō.
 * Susato Mikotoba (御琴羽 寿沙都) - A judicial assistant working alongside Naruhodō. Described as a "yamato nadeshiko" with a progressive frame of mind and a love for foreign detectives. She also has something of a sweet tooth.
 * Sherlock Holmes (シャーロック ホームズ) - The legendary English detective famous for his deductive reasoning who assists Naruhodō with crime investigations.
 * Iris Watson (アイリス ワトソン) - Holmes's assistant. A genius 8-year old girl who has a medical doctorate and is also an author. Takumi's familiarity with the Sherlock Holmes stories, and various theories and parodies in particular, led him to create the Iris Watson character.

Other characters

 * A prosecutor strongly resembling Winston Payne.
 * A bearded man resembling Demitri Demiglass (デミトリ デミグラス), a Russian revolutionary. Holmes and Naruhodō investigate this man while on board a steamship, and engage in "joint reasoning" to find out whether he is indeed Demiglass.
 * A waiter.

Gameplay
The game incorporates the classic investigation and courtroom gameplay of previous Ace Attorney titles. Like the other 3DS titles Professor Layton vs. Phoenix Wright: Ace Attorney and Phoenix Wright: Ace Attorney: Dual Destinies, the game features 3D character models and backgrounds, and also allows for more in-depth background exploration. With the introduction of the character of Sherlock Holmes, a new gameplay feature called "joint reasoning" (共同推理) has the player point out where Holmes is taking his reasoning beyond the truth in order to solve the mystery.

Development
Development began a few months after the November, 2012 Japanese release of Professor Layton vs. Phoenix Wright: Ace Attorney, when Takumi was asked to start work on a new Ace Attorney game. Because the series had become so long, spanning nine text adventure titles, a more accessible title was desired. Takumi thought that it would be fun to combine the Ace Attorney formula with an earlier idea that he had had for a game. The overall game concept really came together with the introduction of the Sherlock Holmes character. He did not actually expect Capcom to accept it.

Announcement
On December 27, 2013, Capcom announced that Takumi was working on a new game that was planned to be presented in 2014. A February 13, 2014 Nintendo Direct event revealed the game was a "totally different" Ace Attorney game for the Nintendo 3DS.

In April 2014, the game was finally given a title and was featured in Famitsu. An interview with director Takumi and producer Kojima described the basic details of the game, including the Meiji period setting, protagonists Ryūnosuke Naruhodō and Susato Mikotoba, and the Meiji period setting. Takumi said that he had not gotten to know the characters very well yet, but that he learned more about them as he wrote more of the script. He also mentioned the challenge of writing dialogue appropriate to the Meiji period, when Japan was focused on becoming part of "the new world" and becoming more Western, which included the Western court system complete with defense attorneys. Kojima revealed that the game is planned to be the first in a series, and that they would show players that the game was capable of being more than just a spin-off.

The Famitsu feature was followed by a teaser trailer for the game. According to Takumi, development of the game had only begun recently. He described this situation as chaotic and was not certain of how the game would turn out, but also said that it was always like this in the beginning of his projects, which was both scary and fun.

Tokyo Game Show
In September 2014, the game was featured again on Famitsu, and introduced Sherlock Holmes and Iris Watson. On September 18, another trailer for the game was released.