Playco is a new mobile gaming startup created by Game Closure co-founder Michael Carter and Zynga co-founder Justin Waldron, as well as game producers Takeshi Otsuka and Teddy Cross. Although the Tokyo-headquartered company is only announcing its existence today, it’s already a unicorn — it says it’s raised $100 million in Series A funding, at a valuation “just north of $1 billion.” The round was led by Josh Buckley and Sequoia Capital, with participation from Sozo Ventures, Raymond Tonsing’s Caffeinated Capital, Keisuke Honda’s KSK Angel Fund, Taizo Son’s Mistletoe Singapore, Digital Garage, Will Smith’s Dreamers, Makers Fund and others.