Koei has performed various third-party collaborations with their products. Consumers can often participate in them by inputing registration codes with a related product. These registration codes can be inputted online through a personal computer or mobile phones to unlock various bonuses for a game. Usually, these codes can be inputted with a Mobile Joy like method. These bonuses are exclusive to Japan.
This list will also strive to include other miscellaneous third party media that don't employ inputting a code into a cell phone. It will also combine expansions packs and spin-offs with its parent title.
General Collaborations
- Any Neoromance series event which meshes the franchises together; any associated Sanrio merchandise
- Söldnerschild
- Boukoku no Aegis 2035: Warship Gunner
- Dynasty Warriors: Gundam series
- Warriors Orochi series
- Fist of the North Star: Ken's Rage series
- One Piece: Pirate Warriors series
- Lovelove ♥ Tenshi-sama Angelique
- Angelique Maren no Rokukishi
- MISS PRINCESS: Miss Puri!
- Pokémon Conquest
- AKB48 no Yabou
- Toukiden
- CR Sengoku no Arashi ~Nobunaga no Shou~ and Sengoku no Arashi ~Kakusei no Shou~
- Sengoku Pachislot Nobunaga no Yabou ~Tenka Sousei~
- CR Nobunaga no Yabou Tenka Sousei ~Nii no Jin~
- Samurai Derby
- moba-nobu
- Hyrule Warriors
- Dragon Quest Heroes series
- Youkai Sangokushi
- Arslan: The Warriors of Legend
- Romance of the Three Kingdoms Maker
- Attack on Titan series
- BERSERK and the Band of the Hawk
- Warriors All-Stars
- Fire Emblem Warriors
- Neo Angelique Tenshi no Namida
- Marvel Ultimate Alliance 3: The Black Order
- Persona 5 Strikers
- Hyrule Warriors: Age of Calamity
Nobunaga's Ambition
Nobunaga no Yabou Tendou
- Various collaboration DLC
- Nobunaga no Yabou Online crossover event
- Special scenario for the live action film, Nobou no Shiro, in the Power up Kit and PS Vita ports
- 100man-nin no Nobunaga no Yabou crossover event for the PS Vita version
Nobunaga no Yabou Sphere of Influence
- CG graphics from this game shall appear in the 2016 Taiga drama Sanadamaru. The Sengoku Risshiden expansion shall include an event dedicated to the drama.
Nobunaga no Yabou Online
- Various netcafe campaigns
- Every Net Entertainment Festa event
- Kunitori Zunoubatoru Nobunaga no Yabou collaboration
- Hikonyan event which allowed players a chance to own their Hikonyan pet
- Sengoku Udon collaboration
- Chacha Tengai no Onna present campaign
- Sengoku Bushou Matsuri serial codes
- Samurai Cats crossover event with SMASH!
- Real Escape Game Owaranai Gassenkara Dasshu serial codes
- 100man-nin no Nobunaga no Yabou crossover event
- Ace Kamon collaboration
- Special item themed to live action film, Nobou no Shiro
- Guntama crossover event
Romance of the Three Kingdoms
Romance of the Three Kingdoms XI
- Zhou Yu, Zhang Liao, and Zhao Yun's portraits from this edition appear in the bonus DVD/Blu-ray episodes of Kuragehime (Maya's episodes)
Sangokushi Online
- Special collaboration with Yahoo!Japan's Sangokushi Tokushu II presentation. Players could obtain Wakaba's trademark mantle in this game.
- Serial codes with Souten no Kouro first volume DVD purchase could unlock bonus content related to anime, such as Cao Cao's punishment club, his trademark line, a wall screen, and the Cao Cao demon figurine.
- Serial codes found on ticket purchase for Red Cliff Part II could unlock a bonus wall screen and a cloak modeled after Zhuge Liang's bird Sangokushi Online
Uncharted Waters
Uncharted Waters Online
- Various netcafe campaigns
- Every Net Entertainment Festa event
- Dream Busters collaboration
- Oceans collaboration
- 2010 Nagasaki Tall Ships Festival collaboration
- FLET'S collaboration with new character armor and sails
- Samurai Cats collaborations for 2011 and 2012
- 100man-nin no Daikoku Jidai collaboration
Ishin no Arashi
Ishin no Arashi: Shippuu Ryomaden
- Special present for registering with game and ticket for the live action film Sakuradamongai no Hen
Dynasty Warriors
Any image song in the series:
- Sora no Kakera
- Can't Quit This!!! ～KNOCK'EM OUT～
- Shenglu ~CIRCUIT~
- Cross Colors
- Ever Free
- Fuun Musouden
- Musou
- Red Cliff ~Ikusa Kokoro~ Shin Sangoku Musou 5 Special Ver.
- Ambience
- Time
Dynasty Warriors Online
- Various netcafe campaigns
- Every Net Entertainment Festa event
- Serial codes found on ticket purchase for Red Cliff Part II could unlocks equipment found in the movie.
- Samurai Cats collaboration
- Road to Dragons collaboration
Dynasty Warriors 6
- Serial codes with Souten no Kouro first volume DVD purchase could unlock bonus edit character parts for the Souten no Kouro Cao Cao and Liu Bei in the Empires spin-off
- Special scenarios and items various video game magazine publications in both titles
- Serial codes with Shigekix purchase unlocks exclusive items for characters' usage
Dynasty Warriors 7
- Serial code with early purchases at Lawson chain granted special weapons and costumes for Wang Yuanji
- Serial code with Sangokushi DVD box set grants a small bonus for buyers
- Yoshimoto Performance Group with their Yoshimoto Musou collaboration; also appeared on Tokyo Game Show stage events for its spin-offs to play the game live for fans
- Pepsi Nex campaign
- Dengeki Playstation bonus for Next
- Chimney Group collaboration
- 100man-nin no Shin Sangoku Musou collaboration
- Minna to Isshou collaboration with Toro and Kuro edit character parts
- Shin Sangoku Musou SLASH collaboration
Samurai Warriors
Any image song in the series:
Samurai Warriors 3
- Various store bonuses for early purchases of Samurai Warriors 3
- Kome Sengoku Musou
- Sengoku Bushou Matsuri was mainly themed to this title
- Special tie-in with the live action film, Nobou no Shiro, featuring both Mitsunaris in promotional posters; Oshi Castle stage is also counted as a collaboration with the film
- 100man-nin no Sengoku Musou collaborations in both Empires and Special
- Various Japanese store chains in Empires DLC
- Samurai Cats collaboration with Special
- Chimney Group collaboration
- Real Escape Game Owaranai Gassenkara Dasshu collaboration
- Pokémon Conquest based select characters portraits on this entry
- Bs Osaka Natsu no Jin collaboration
Samurai Warriors 4
- Hello Kitty collaboration
Fist of the North Star: Ken's Rage
- Collaboration with Comic Bunch and Weekly Famitsu
Neoromance
- Any B's Log or Lala collaborations
- Any musicals or theatrical productions
Harukanaru Toki no Naka de
Harukanaru Toki no Naka de 3
- Sanrio collaboration for Hello Kitty figurines of the Hachiyou.
Kiniro no Corda
- Social game collaborations with Lovelove ♥ Tenshi-sama, Angelique Maren no Rokukishi, Miss Princess: Miss Puri!, and 100man-nin no Harukanaru Toki no Naka de
Kiniro no Corda 3
- Tie-in with Yamaha's Silent Violins. Used by two of the game's characters, Chiaki Tohgane and Housei Toki.
- pivix and B's Log Bunko illustration and short story contest.
Zill O'll
TRINITY: Souls of Zill O'll
- Serial code with Dream's single, Hands Up!, to obtain rare items by registering code into game. Also the group's image songs for the game's ending credits and commercials
- Nico Nico Seiga fanart contest
Winning Post
Winning Post 8
- Collaboration with Tokyo City Keiba
100man-nin no Winning Post
- Guntama crossover event
Pop Cutie! Street Fashion Simulation
- Collaboration with comic, Kabushiki Gaisha Love Cotton.