This helmet I bought in Japan early 2013 for a friend in France who asked me to purchase the helmet for him. A closer look here in Holland revealed that it is dated MARCH 1917 on one of the brails. A closer look after some light cleaning by my friend in France revealed that the helmet is also marked NIPPON SENSUI CO on another brail, and that the bonnet, breastplate and brails have matching serial numbers. The helmet is in a great untouched condition, except for the communications port at the back of the helmet which seems to be added more recently.