Traders in Europe will be waking up to a nervy currency market after the yen's sharp reversal from its slide past 160 per dollar on Monday had some speculating Tokyo could be behind the move while the country was out on a holiday. The jump in the yen - which took it to a session-high of 156.55 per dollar - came just a few hours after it slid to the weaker side of 160 per dollar for the first time since 1990, marking a fresh 34-year low. Some said the rapid strengthening of the yen smelt like intervention, but markets will have to wait till Tuesday for any signals from authorities.