Although it is sometimes called simply 'introduction of Buddhism,' the expression 'official introduction' is often used because it had been already introduced as a private belief before the official introduction as mentioned below.
単に仏教伝来と呼ぶこともあるが、後述のごとく公伝以前に、すでに私的な信仰としては伝来していたと考えられるため、「公伝」と称されることが多い。