TOKYO, Nov 21 - Japan's consumer price index (CPI) for October will probably be unchanged year-on-year, with a jump in rice prices helping offset deflationary pressures, according to a poll of economists by journalists. The poll of 26 economists yielded a median forecast of no change in the nationwide core CPI compared with a year earlier, after a drop of 0.1 percent in September. If that is the outcome, it would be the first time in over four years that the index has not fallen year-on-year. Two respondents forecast a fall while the rest forecast either a flat or positive reading. "With rice prices rising from the start of October, the year-on-year change in core CPI is expected to have turned positive," said Hitoshi Asaoka, an economist at Mitsubishi Research, who forecast a rise of 0.1 percent. The core CPI excludes volatile fresh food prices. Core CPI for the Tokyo area in November is expected to fall 0.1 percent from a year ago after a drop of the same magnitude in October.//