According to the twitter of Hachiya Seiichi, the producer of Kadokawa Shoten, the first trailer of Itsuka Tenma no Kuro Usagi
was removed by Youtube administrators due to the violation of the guidelines. The trailer was posted on Kadokawa's official anime channel.
Itsu Ten Trailer re-uploaded by a user
Hachiya said ecchi and violent factors were indispensable for the entertainment of Itsu Ten anime. He also revealed that the first episode of the anime was rejected by the TV company because of sexual and violent scenes. The staff are now editing the episode to meet the regulation of the TV channel. The uncensored edition will be released in the Blu-ray & DVD.
Source: Hachiya's twitter