Ramusake is a private members restaurant and club on Old Bromtpon Road. It is located in the place where Old Brompton club (also private members) used to be, where I have been a few times. I am not a member at Ramusake and neither are my friends, but as it was our first time visiting them and the place is new, they let us into Ramusake to have dinner and then we could decide whether to join them. Membership costs £250/ year, which is not expansive when compared to what some of the other clubs in London cost, but I was not tempted to join.
Ramusake is a fun place created by Scott Hallworth (ex Nobu and Kurobuta) and Piers Adams (expert on cocktails, music and vibe). I love Kurobuta, it is one of my favourite casual London restaurants and the menu in Ramusake was similar, only shorter, and most of the dishes on Ramusake menu, I had either seen or had in Kurobuta. Also I thought prices maybe were a bit cheaper at Kurobuta, but I am not sure, and would not like to bet on it.