1. Bachi and kabuto
A samurai helmet is called kabuto. Its main part is the iron bowl, called hachi or bachi. This is the most important part of the helmet, the one protecting the samurai’s head. Original antique samurai suits of armor always include a kabuto with a thick and resistant bachi,
A bachi is then equipped with a neck protection, called shikoro, with a decoration for the hole on the top (hachimanza) and a decoration on the front, called maedate.
When judging a kabuto be aware that the bachi is what you want to look at; don’t get distracted by fittings and decorations. They might have a value, of course, but what you are really buying is the iron bowl. Japanese important armor makers were actually creating this part only, while other fittings were added by other craftsmen.
2. Look inside
If the bowl is not fitted with a cloth linen (called ukebari), you are able to look inside the kabuto and appreciate how it was built. You can have many informations about age and quality of a Japanese helmet just looking at how the plates have been cut and assembled. Also, this is the place where signatures and dates are inscribed by the armor makers.
3. Familiarise yourself with patina
A kabuto is never left uncoated, as iron would oxidise immediately. There are many types of surface treatments, but all of them change as time goes by, creating some sort of patina. Patina is a strong indication of the age and authenticity of iron. As kabuto are exposed to various elements the iron is impacted, resulting in patina, with a change in the texture and colour of the helmet’s surface.
4. Know types of kabuto
Kabuto can be constructed in many ways, some simpler, with a limited amount of plates and workmanship, and some more complicated and difficult to make. Not always the most flamboyant kabuto, and there are many for sale, are the more difficult to build. You should know the basic models of a kabuto: zunari kabuto, momonari kabuto, suji-bachi kabuto and ko-boshi kabuto. You should be aware, for instance, that the construction of a 120-plates kabuto is way more difficult, and hence valuable, than the construction of a momonari helmet. Understanding quality and construction features of each type will help you in understanding age and value.
5. Look at as many examples as possible
Museums are ideal for training your eye and learning about various stylistic traditions. Dealers’ galleries and exhibition visits offer the added advantage of allowing viewers to handle works and ask specialists questions. If you cannot visit a museum or attend a dealer’s exhibition, websites such as giuseppepiva.com allow you to zoom in on the fine details of japanese armors.
Finally, invest in some reference books. There are many exhibition’s catalogues that would show you the best quality samurai’s kabuto so you can train your eyes.