Stone Wall Renovations and Discoveries
In 2016 and 2017, extensive maintenance was performed on the stone walls lining the inner moat near Himeji Castle’s main entrance. Built in the uchikomi-hagi (wedged-stone wall) style, this section of wall is attributed to Ikeda Terumasa (1565–1613), the daimyo lord who expanded and renovated the castle at the start of the seventeenth century. To repair the wall, workers carefully removed stones that had been pushed out of place by tree roots, dug out the roots, and slotted the stones back in place. They also replaced fallen mazume-ishi, small rocks that fill gaps between the larger ones. The process taught researchers much about the materials and construction techniques used to build the wall.
Drainage
Between the visible outer stones and the earth behind it is a 0.5- to 1-meter thick layer of small, fist-sized stones. Called uragome, these rocks allow rainwater to drain away rather than collect behind the outer stones, protecting the wall from collapse.
Wedge Marks
Stones used in uchikomi-hagi walls have rough, unworked surfaces. However, when workers removed blocks from the wall, they found evidence that some of the stones came from great boulders that had been split into smaller pieces. These stones still bear the marks of wedges used to split them. In some cases, workers could use the wedge marks to match stones that originally came from the same boulder.
Stone Wall Markings
When workers took the wall apart, they also found a mark inscribed on one of the stones: a circle with a line cutting through its center. It was not the only one; some 50 different symbols have been found on Himeji Castle’s stone walls, almost 90 markings in total. Their meaning and purpose are not fully understood, but they may have been quarry marks indicating the source of the stone, symbols identifying the team of builders that installed the stones, or inscriptions designating where the stones would be placed.
