I am not keen in many of the Japanese dramas as tonnes of them has been a disappointment with either crap acting (putting looks/slutty/school-girl-cutey attire over acting skills) or just a dire story. However, my all time favourites are:
Hanzawa Naoki (frigging awesome. It's the Kaiji anime of TV dramas)
and
Saki
Notable mentions are:
Gokusen (Series 1, 2 and 3)
Kuroyuri danchi
Shomuni (Season 1 & 2 only, forget season 3)
I watch a few others now and again on Abema TV and on normal TV when I have time.
Hanzawa Naoki (frigging awesome. It's the Kaiji anime of TV dramas)
and
Saki
Notable mentions are:
Gokusen (Series 1, 2 and 3)
Kuroyuri danchi
Shomuni (Season 1 & 2 only, forget season 3)
I watch a few others now and again on Abema TV and on normal TV when I have time.