Japanese rubber futures edged higher on Tuesday as stronger oil prices helped boost investors" risk appetite while a weaker yen against the U.S. dollar also lent support. The Osaka Exchange rubber contract for June delivery , was up 0.4 yen, or 0.2%, at 243.3 yen ($2.1) per kg, as of 0336 GMT. Oil prices rose to a more than seven-year high on worries about possible supply disruptions after Yemen"s Houthi group attacked the United Arab Emirates, escalating hostilities between the Iran-aligned group and a Saudi Arabian-led coalition. The Bank of Japan upgraded its inflation forecasts and left unchanged a -0.1% target for short-term interest rates. read more The dollar traded at 114.88 yen , against 114.48 yen in late Monday trade in Asia. A weaker yen makes yen-denominated assets more affordable when purchased in other currencies. The rubber contract on the Shanghai futures exchange for May delivery was down 25 yuan, or 0.2%, at 14,880 yuan ($2,346) per tonne. The front-month rubber contract on Singapore Exchange"s SICOM platform for February delivery last traded at 180.4 U.S. cents per kg, up 0.7%. TOKYO, Jan 18 (Reuters) - ($1 = 6.3414 Chinese yuan) ($1 = 114.9200 yen)