% Expired Patents = 40.0

Trademarks = 18

Forward Citations = 157

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8 inventors (with patents filed for the assignee):

Jumpei Tsuda (3 out of 3 patents)

JaeYoung Kim (2 out of 2 patents)

Yoichi Erikawa (2 out of 2 patents)

4. Junpei Tsuda (1 out of 2 patents)

5. Takao Kato (1 out of 38 patents)

6. Takashi Atsumi (1 out of 1 patent)

7. Tomokazu Takeda (1 out of 1 patent)

8. Satoshi Nakamura (1 out of 50 patents)

5 patents: Sort by Forward Citations

1. 7104890 - Program, recording medium, game character rendering method, and game apparatus (2006-09-12),

2. 6894688 - Program, recording medium, rendering method and rendering apparatus (2005-05-17),

3. 6736724 - Character group battle method, recording medium and game device (2004-05-18),

4. 6729954 - Battle method with attack power based on character group density (2004-05-04),

5. 6525736 - Method for moving grouped characters, recording medium and game device (2003-02-25),

Company Overview

Koei Co., Ltd. is a Japanese video game developer and publisher known for their historical simulation games such as the Romance of the Three Kingdoms and Nobunaga's Ambition series. Founded in 1978, the company has since expanded its portfolio to include various genres of games on multiple platforms. Koei Co., Ltd. continues to be a prominent player in the gaming industry with a strong focus on delivering immersive gaming experiences to players worldwide.

Profile summary synthesized from public USPTO records and patent filings.

Company Badge

USPTO Data Jan 1 1976 - Oct 20 2026

5 Patents

#118 in Yokohama

#6,654 in Japan

Yokohama, Japan

Koei Co., Ltd.

Forward Citations = 157

8 inventors:

Jumpei Tsuda (3 out of 3 patents)

JaeYoung Kim (2 out of 2 patents)

Yoichi Erikawa (2 out of 2 patents)

4. Junpei Tsuda (1 out of 2 patents)

5. Takao Kato (1 out of 38 patents)

IDiyas Innovation Intelligence. (2026). Company Patent Portfolio: Koei Co., Ltd.. Retrieved from https://idiyas.com/company/koei-company

Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile

Data Sources: USPTO Patent Grant XML, Patent Center, EPO & CIPO • Normalized by IDiyas Innovation Graph. Methodology & provenance architecturePlease report any incorrect information to [email protected]