Uchiyama, 34, was taken the distance for the first time in four years but took the decision 117-110 on each of the three cards.
Fighting on New Year’s Eve for the third straight year, he gave more than he got against Kaneko in a wide-open bout between two hard hitters, opening a cut near the challenger’s right eye and leaving his left eye nearly swollen shut.
A right hook dropped the champion late in the 10th round but Uchiyama wasn’t badly hurt and he came back strongly in the final two sessions.
“Kaneko was strong,” he said. “He’s the man. I’m the world champion, but he provided me with a good experience.
“I was surprised, but I knew what the count was. I didn’t panic and stood up. It was OK.”
Earlier in the evening, Takashi Miura successfully defended his WBC super-featherweight belt for the second time, stopping Dante Jardon by TKO in the ninth round.
The southpaw dominated throughout, knocking the Mexican down in the fifth, then again before referee Len Koivisto stepped in and halted the match 55 seconds into the ninth round.
Miura has now won seven straight fights since losing his first fight to Uchiyama, including a ninth-round TKO of Mexico’s Gamaliel Diaz in Tokyo last April for the WBC belt.
His win has inevitably led to calls for a rematch and unification bout between the pair.