* Nikkei 225 Stock Average: +178.03 (+0.99%) to 18,149.52; highest close since 2/27; ytd & multi-year set 2/26
* Nikkei 225 futures Osaka: +180 (+1.0%) to 18,200
* TOPIX: +15.45 (+0.87%) to 1,788.39; Advancers 1,236 x decliners 361 (unchanged 135); new highs 119 vs. new lows 6
* Jasdaq: +0.75 (+0.91%) to 83.21
* USD/JPY ~123.5 at 4.5 yr low; near all-time low vs. euro; 16-year low vs. AU$