I believe that that may have actually been a lightly armored artillery tractor similar to a Bren Gun Carrier...

Japanese tanks were only feeble when compared to their Western counterparts...They were effectively used in situations where there were none opposing them (Singapore, China) and where the enemy anti-tank and armor capability withered (the Philippines). And the Imperial Japanese Army was adept at employing them in such circumstances.

There were some decent tanks designs that were roughly on par with a Sherman, and even one that would have even given the Pershing (which was deployed for the invasion of the Japanese home islands) a run for its money.

Towards the end of the Pacific campaign, tanks in island garrisons were largely a waste of resources as placing guns in the underground labyrinths and bunker fortresses were much more effective, and cheaper. And the terrain usually prevented US tanks from maneuver essentially forced them to adopt the role of direct infantry support as "mobile pillboxes". Though, there were tank to tank encounters between Marine and Army units and the IJA. The 75mm gun on the Sherman, considered inadequate against German armor by the end of 1942 was still too much for the typical Japanese tank, and often they used high explosive rounds to demolish them, because AP would just pass right through the thin Japanese armor often with little effect unless it was a direct head on hit.

Here are a couple of related threads:

Type 5 "Heavy Tank" - WW2inColor Talk
Type 3 medium tank Chi-Nu - WW2inColor Talk