This Toppai-Nari kabuto is the heaviest kabuto I have ever held with the hachi weighing in at 4.5kg. It has been made from eight 10mm thick iron plates and reflects the gun paranoia that was sweeping the Japanese battlefield during the momoyama period.
The helmets surface was russet iron but had originally be coated in an urushi russet iron effect called tetsu-sabiji-nuri. As the original urushi had been removed there were a number of gaps between the plates, exposed rivets and some rusting.
The shikoro neck guard had a broken fukigashi ear and the fukurin upper rims on each lame of the shikoro were broken away. The odoshi silk lacing had also perished with the lames being strung with some jute string.
My task was to repair the damage and return the outer surface to its original condition. 90% of the commission being urushi based.
After removing any active rust I coated the russet iron in a layer of urushi. I filled all the gaps between the ken with kokuso. The largest gap was between the hachi and the Maebashi visor. The actual kabuto construction was a bit wabi-sabi but that reflects the character of the piece.
On the top of each lame on the shikoro, the artificial rim or fukurin was missing, I had to sculpt the rims back in place. Kokuso is made from rice flour mixed with fine sawdust and urushi, it makes a sticky putty-like material that can take up to eight weeks to harden. Kokuso remains hard but retains a certain amount of flexibility, so if the lames are compressed the kokuso bends whereas a modern filler would break off. This is another reason why traditional materials have to be used in restoration. The fukigashi was repaired using some 0.5mm mild steel and two steel pins as rivets.