The Birth of PlayStation

From 1989, Sony had been secretly co-developing a CD-ROM add-on for the Super NES with Nintendo. Its internal code name was the Nintendo PlayStation. Ken Kutaragi led the project. At CES on May 28, 1991, Sony announced the partnership. The very next day, Nintendo announced it had signed a deal with Sony's rival Philips for a CD-ROM drive serving the exact same purpose. The reversal happened in public, within a single day. Sony reworked the project into a standalone PlayStation and released it in December 1994, which went on to outsell Nintendo's home consoles. A rival born from a falling-out. Note: several articles report what Kutaragi said at the time, but I could not confirm his own primary statements.