In November 1983, murals were first discovered using a fiberscope to photograph the interior of the stone chamber. Two subsequent surveys were also conducted with the technique of probing the chamber interior by inserting only a camera. This was to preserve the environmental conditions within the chamber, including temperatures of 15–18°C, humidity at nearly 100%, and the composition of the air, by not suddenly allowing outside air to enter.
Meticulous survey of the interior with three types of cameras
First survey, November 1983
Inserting a guide pipe diagonally into the stone chamber through the looting hole, photographs were taken by inserting a 30,000 pixel fiberscope made by bundling 30,000 fibers that were each one-tenth the thickness of a human hair. Shortly after starting, the Black Snake-Tortoise mural was discovered at a rather high position on the north wall. It thus became clear that this was the second tomb with murals after Takamatsuzuka. This fiberscope survey was conducted by NHK at the request of the Association to Honor the Ancient Capital of Asuka.
Second survey, March 1998
Fifteen years after the first survey, with great advancements made in camera precision and filming techniques, photographs were taken at 400,000 pixels, more than ten times the previous resolution. In this survey, the Blue Dragon, White Tiger, images of the sun and the moon, and the celestial map were discovered. These results were made possible by a compact CCD camera that could be remotely operated to point up, down, left, and right.
Third survey, March 2001
A 3.34 million pixel digital camera was used in the third survey. In addition to pointing up, down, left, and right, this camera was also able to swivel its lens to face the rear, and the Red Pheonix, which had been lost through damage at Takamatsuzuka Tumulus, was discovered. Images were also obtained of what appeared to be zodiac figures with animal heads and human bodies. Further, conditions of the wall plaster and the temperature and humidity, important conditions for determining future preservation policy, were accurately assessed, thus exploring the feasibility of preservation work.