Contains news concerning Koei Tecmo's activities in the year 2009.
January
- Musou Orochi Z has been announced for the PlayStation 3.
- Meng Huo is set to appear as a playable character again in Dynasty Warriors 6: Empires.
March
- A major patch had been installed for Dynasty Warriors Online.
April
- Video game companies Koei and Tecmo merge to create Tecmo KOEI Holdings Co.
June
- Musou Orochi Z is confirmed to be a Japanese-only title.
- Dynasty Warriors 6: Empires is given a release date for overseas regions.
- Koei announces four new titles at E3: Monster Races for the Nintendo DS, Warriors Orochi 2 for the PlayStation Portable, and Warriors: Legends of Troy as well as TRINITY: Souls of Zill O'll for the PlayStation 3.
July
- A PlayStation 3 and Xbox 360 conversion of Dynasty Warriors: Strikeforce was announced for Japan and will be out in stores on October 1. It is titled Shin Sangoku Musou Multi Raid Special.
- Dynasty Warriors Online will be updated with a new patch titled Revolution 4. It enables players to equip Cao Ren, Zhou Tai, and Yue Ying's weapons.
- Koei is performing a collaboration event with the anime Souten Kōro in three of their titles.
August
- Four new characters have been identified for Samurai Warriors 3.
- Meng Huo, in his new appearance from Dynasty Warriors 6: Empires, will also be included in Shin Sangoku Musou Multi Raid Special.
September
- Koei-Tecmo's website regarding their TGS 2009 booth opens. Twenty-one games will be presented and special events will be held for Samurai Warriors 3 and Nobunaga no Yabou: Tendou.
- Sangokushi Online will be updating to include Nanman designs.
October
- The official site for Samurai Warriors 3 has updated with more information regarding characters and the Nazo no Murasamejo mode. Voice clips and trailers are now available.
- Dynasty Warriors 6: Empires will be ported to the PlayStation Portable.
- Koei's "mystery title" from TGS 2009 is a Warriors version of the Fist of the North Star (Hokuto no Ken) anime. Videos of the October 14th press release are now available for normal viewing on Niconico Douga.
- Dynasty Warriors Online will have Yue Ying's weapon available on October 20th. The fourth tie-in event with Souten Kouro is a side quest for Wei during the Battle of Mt. Ding Jun.
November
- A sequel to Dynasty Warriors: Strikeforce is announced. One of the new characters includes Da Qiao.
- More characters confirmed in Samurai Warriors 3. There is also information about the online shopping features available for the game.
- Dynasty Warriors Online is updating to Revolution 5 on November 17th. The new story scenario for this patch is conquering Jing Province. Players can also gain access to Zhen Ji, Sun Ce, and Huang Zhong's weapons as well as a panda pet to fight for them. The Self-Torture Ruse planned by Zhou Yu and Huang Gai can also be done as a new mini-quest.
- Musou Orochi Z released for the PC in Japan.
December
- Producers for Dynasty Warriors: Strikeforce Special and Samurai Warriors share their closing thoughts on the year's progress with 38 other game developers. They reveal their own personal favorite game genres, their private choices as the year's best titles, and their expectations for 2010 here.
- Koei has announced their intentions to host a Sengoku Jidai themed event on January 7th, 2010.
- Hokuto Musou has updated its official site to include individual character renders and other screenshots for the game. Toki is also confirmed to make an appearance in this particular title.
- Koei will be present at the 2010 Jump Fiesta event. Their booth will feature voice actors and events from both Shin Sangoku Musou Multi Raid 2 and Samurai Warriors 3.
- Dynasty Warriors Online is updating on December 17th to include Sun Ce's weapon for players and a side-story surrounding the Battle of Chang Ban from Liu Bei's perspective.
- Dynasty Warriors: Gundam 2 is one of the game titles included in the Gundam franchise's 30th anniversary collection. It is repackaged to include the anniversary logo.