Actually they are from Himeji Castle, so they could be part of a rack, although the flat bits look to have been hammered flat against a surface. Every so many years they do a great refurbishment there. This is happening at the moment. These nails came from the previous time they were working on the castle, apparently, but for what they were originally used I cannot say. The paper twist says "Himeji Castle" in rather old brushwork. I can't find the actual nails any more, so I suspect I may have given them to a swordsmith to mix in with his Tamahagane.
In the middle is sword-making iron sand from a river in Hyogo, just east of Bizen, showing how iron shows up in this area of Japan. The earliest iron foundry in Japan is just west of here at the foot of Ki-no-Jo Castle in Soja, and the oldest 'Dou' breastplate in Japan was unearthed near there.
On the right is teppo-making iron sands from the beaches of Tanegashima, where guns came ashore and where they were first manufactured in Japan, in 1543. There must have been a sword-making industry there already.
The little packet on the left also contains some of this iron sand and shows the outline of Tanegashima Island, in the shape of a seed, thus the name. On the packet it says Teppo Denrai (Arrival of guns in Japan)Tanegashima San (Product of Tanegashima). Oh, and the little label at the top was a smokescreen - a ticket stuck to the packet by the shop saying Great Fortune (Dai-kichi 大吉) Good health today too (Kyo mo genki de 今日も元気で) and underneath that ... mmm enjoy your food! (?) (Gohan ga gu ご飯がグツ)