1 ping from a .50 cal and there tanks would be dead. Most of them had such poor armor that they could be knocked out with small arms fire.
Myth.
Armor Quality
As has already been discussed, Japanese armored vehicles were very
lightly constructed, by Western standards. This was, primarily, a result of
Japanese experiences in Manchuria and tropical theatres of war, both of
which had shown heavy vehicles to be a severe liability. Indeed, the
deployment of heavier armored vehicles such as the Sherman and
Matilda II in the Pacific had shown that this experience was not unique to
the Japanese, and many of these heavier vehicles were simply useless
until properly adapted. A great many heavy vehicles were lost, even after
these adaptations, to the machinations of weather, terrain, and clever
infantrymen experienced in taking advantage of the weaknesses of such
vehicles in such circumstances.
The armor protection of Japan's heaviest vehicle to see combat during the
second world war, the Type 1 Chi-He, was approximately 8-50mm thick,
with a welded hull. This was superior to the protection of the M3/M5 Stuart
(the most commonly deployed Allied vehicle in the Pacific). The 50mm
front turret glacis, however, was nearly 49mm thinner than that of the M4
Sherman with which it had been designed to contend, with armor varying
from about 13 to 89mm thick. The most commonly encountered Japanese
medium tank, the Type 97 Chi-Ha, was by comparison only 8-25mm thick,
considerably less effective than the 10-44mm thick armor of the M3/M5
Stuart. The armor of the Type 95 Ha-Go light tank, Japan's most common
vehicle, was nowhere near either vehicle in terms of protection.
ack-ack