Benchmark Tokyo rubber futures extended losses into a fourth session on Wednesday, diving to a one-month low as a continued slide in Shanghai futures prompted fresh selling. The Tokyo Commodity Exchange (TOCOM) rubber contract for February delivery finished 1.2 yen, or 0.6 percent, lower at 212.2 yen ($1.9) per kg, after having earlier touched 209.5 yen, its lowest level since August 15.