‘Cross-Border Investigation’ (Ekkyō Sōsa) is a series of Japanese police novels by Ryōhei Sasamoto. It has been published by Futabasha since 2006. It has been adapted into television dramas on the TV Asahi and TV Tokyo networks. A one-off special episode was broadcast on the TV Asahi network on 11 September 2008. The second instalment, ‘Provocation’, was broadcast on ‘Saturday Wide Theatre’ on 22 May 2010, whilst the third instalment, ‘Rupture’, was broadcast as a drama special on 22 December 2011. Kyohei Shibata starred in both.