Futon enables Katai to manipulate any electronics within his sight as long as he is not touching them. Moreover, his ability allows him to process information dozens of times faster than an average human and can be considered to even rival the military's information warfare units. Additionally, Katai can only seemingly concentrate on using his ability with optimal efficiency wherever his body and mind are most relaxed, which Doppo Kunikida mentioned to be when he is wrapped in his futon named Yoshiko. Nonetheless, Katai has shown to use his ability even without Yoshiko, able to change the signal of a pedestrian traffic light once with his ability. Aside from simultaneously manipulating several computers with his sight, Katai can also remotely control communication lines at quick speeds with his ability.
Prior to joining the Armed Detective Agency, Katai was constantly hired by various corporations to use his ability as a white hat hacker in order to steal information on their networks and assess their system countermeasures against potential malicious hackers. Despite the rigor and complex nature of such tasks, Katai completed them at an average rate of mere hours. A month before he decided to join the Agency, Katai once helped Kunikida with an Agency request from the daughter of a wealthy man to trace the whereabouts of her elusive stalker, a task that proved to be tedious for Kunikida and the police. Within three hours after he agreed to help out, Katai was able to trace the stalker's location, including his residence, workplace, where he was from, and even his bank account.
The ability is based on Futon (蒲団, Futon?, alternatively "The Quilt") written by the real-life Katai Tayama in 1907, which is considered as the work that cemented his reputation. This work also became one of the precursors to the Japanese genre known as the I-novel (私小説, shishōsetsu?), a form of confessional literature where the plot of the story corresponds to events in the author's life. The novel recounts in embarrassing detail the unconsummated attraction and obsession of a middle-aged writer towards his young, idealistic female student named Yoshiko, the namesake for the in-series Katai's signature futon.