In Higurashi’s various console releases (Matsuri, Kizuna, Sui, etc.), there are a few arcs not present in the original series. These arcs sometimes introduce new characters, shed some light on the background events on the series, or present new scenarios altogether. While not written by Ryukishi07 himself like the original arcs, they were written by Alchemist with his input and direction. This thread is for people to discuss these various arcs.
- Taraimawashi: What if, in Onikakushi, Keiichi had decided to trust Mion and Rena? This arc sheds a lot of light on the history of Hinamizawa and the mystery surrounding it.
- Yoigoshi: A retelling of the original manga chapter with some additional characters. A group of young adults comes to the abandoned village of Hinamizawa, where they meet a woman claiming to be Mion Sonozaki seeking to protect the Sonozaki family.
- Tsukiotoshi: An arc that centers around Keiichi, Rika, Shion, and Satoko. Similar in nature to Tatarigoroshi, except this time, Keiichi, Rena, and Shion all work together to rescue Satoko by any means necessary.
- Someutsushi: A retelling of Onisarashi, the manga arc featuring Natsumi Kimiyoshi, with slightly different events and some new characters. Natsumi, a girl who lives in Okinomiya with her family, has her life thrown into chaos thanks to events in Hinamizawa.
- Kageboshi: Another mutation of Onisarashi. Follows the story of Minai Tomoe, a policewoman who is investigating the events in Hinamizawa and Okinomiya. Working with Akasaka and Ooishi, she investigates the circumstances of Natsumi and her family.
- Tokihogushi: An arc featuring Rena, Tomoe, and Nagisa Ozaki, a former classmate of Rena’s and relative of one of the boys Rena attacked. This arc sheds light on Rena’s background before moving to Hinamizawa.
- Kotohogushi: This arc (originally included in Miotsukushi) is the story of Hanyuu in the days of feudal Japan. It introduces the ancestors of the Furude, Sonozaki, and Kimiyoshi clans and provides a look at Hinamizawa during ancient times.
- Miotsukushi: An alternate ending to the series wherein Rika and Keiichi work together to try and prevent all of the tragedies of the series, only for new complications to arise. It deals with a lot of character arcs not resolved in Matsuribayashi, particularly involving Mion and Shion.
While unreleased outside of Japan, these arcs have some fans overseas. The most recent release, Higurashi no Naku Koro ni Sui, was released in April 2015 for PS3 and Vita by Kaga Create, which has since gone out of business while developer Alchemist has declared bankruptcy. You can still find copies on Amazon, but marked up considerably (PS3, Vita). It contains the vast majority of these arcs as well as all of the original ones (as well as some bonuses).
In the interests of not spoiling those who haven’t had a chance to play through these particular stories but may wish to, please make liberal use of the [spoiler] tag!