"The thirteenth series of Merzbow's archival series, which began in 2018 and focuses on unreleased and unearthed material, includes six albums recorded between 2011 and 2012: Insect 801, Kumo No Zettaichi, Sugamo Flower, Bit Blues", "Kotorhizome", and "Gman+". Horizon" is a boxed set of these works. In 2011, Merzbow released "Dead Zone" on the Ukrainian label Quasi Pop Records, which focused on the radioactive contamination caused by the nuclear accidents in Fukushima and Chernobyl, and also released "Uzu Me Ku" (Samboy Get! Recordings, 2012). (Samboy Get! Recordings, 2012), which shows a photo of the Nagasawa water purification plant with cracks in the columns caused by the earthquake. The "Kamadhenu", "Surabhi", and "Gomata" trilogies on the theme of "sacred cows", which were commissioned by Hypnagogia (UK), continue the theme of animal rights. However, it was also a time when a gradual shift to less direct animal rights themes could be seen, such as in "Lop Lop" (Rustblade, 2011) and later "Konchuuki" (Essence Music, 2015).

In addition, the introduction of new equipment such as small oscillator synths, drone machines, and minikoto (miniature harpsichord) strongly characterizes the sound.
The six albums in this collection have in common the extensive use of oscillator synths and drone machines to create drones with unique textures, but the final style differs in many ways: some have a rhythmic approach to them, some are thicker and louder with noise, and some maintain a calmness that changes gently throughout." - Yorozu