Umineko no Naku Koro ni Murasaki: Forgery of the Purple Logic (うみねこのなく頃に紫 Forgery of the Purple logic) is a manga-exclusive series by Kurumi Suzuhiro. The story expands on the use of the Purple Declaration introduced by Bernkastel in Twilight of the Golden Witch. The Red Truth still applies in this game even though there are lesser than usual games. Knox's rules are stated in red to show that it is valid in this game. It has not been translated yet nor has it been licensed for release outside Japan. The story takes place outside the main story.
After winning a game against Battler, Beatrice starts another game. Only this time, she decided to start a game that does not have magic making it just a game focused on whodunnit. If Battler loses again, it would mean he really is incompetent. Erika only exists on the gameboard as the detective trying to solve the mystery. The story ends with both Erika and Battler claiming they had solved the mystery and a challenge issued to the readers.
Differences from main games
- There are no fantasy scenes in this game, therefore Beatrice does not appear on the gameboard like in the other games.
- Shannon is not on the island in this game.
- Kinzo Ushiromiya is treated as alive until the game starts as there was no magic.
- There are exactly 18 people on the island counting Kinzo and Erika while removing Shannon.
- There are mutiple culprits similar to Bernkastel's game in Twilight of the Golden Witch.
Just before the explosion, Erika reveals one of the culprits to the remaining survivors. However there is still at least one other culprit. Hints are scattered across the game with the main one being that one of the culprits is a female and someone who hates the Ushiromiya family.
In the challenge page,the author listed three questions for the readers to answer.
- Please answer which culprit killed who under the situation that there is more than one culprit.
- Please answer who is the last person to be killed until Chapter 9.
- Please explain how the crimes are commited.