Sekizoku (a flint arrowhead) (石鏃)

Sekizoku is a type of stone tool also called a Yajiri (arrowhead; 鏃 or 矢尻 in Chinese characters).

Sekizoku was developed as the usage of Yumiya (a bow and arrow) started in the Jomon period and it was used during Jomon and Yayoi periods mainly as a hunting tool.

Sekizoku is classified into three structural types depending on the shape of ki-hen (the base); Hei-ki (flat base), which had a straight base, concave base, which had a depression, and convex base, which had a projection. Sekizoku can be also classified into the following four types depending on the presence or absence of nakago (a stem; a projection area); the flat base type (without nakago), the concave base type (without nakago), the convex base type without nakago, the convex base type (with nakago).

Sentoki (points) of the Paleolithic period is similar stone tool to Sekizoku. Konohagata (a leaf-shape) Sentoki was used as a lance and Yuzetsu Sentoki (points with projection) was used as a dart. Length and weight of the former Sentoki vary greatly. Length and weight of the latter Sentoki were uniform.

Yajiri (arrowheads) of the Jomon period were thin and triangular-shaped. On the other hand, arrowheads of the mid-Yayoi period in the Kinki region were made to be thick and heavy and most were leaf-shaped while some were triangular-shaped. Their weights were equivalent to the weight of the arrowheads made from iron or bronze. The heavier the arrowheads became, the more damage they caused. Arrowheads of the early Jomon period were made light, so they were able to fly fast and far to hunt deer and wild boar effectively. Light weight arrowheads were used until beginning of the Yayoi period; however, the bigger and heavier arrowheads which could penetrate deeper started to be used in the Kinki region between the first century before Christ and the first century of the Christian era. In other words, the use of the arrowhead as weapons increased.

The majority of Sekizoku weighed less than two grams and was between one and three centimeters in size throughout the time until the beginning of the Jomon period to the beginning of the Yayoi period. These findings revealed that there were no major changes in the overall design of hunting equipment for a long period of time. Sekizoku, which was easy to penetrate deeper, suddenly appeared in the Kinki region during the Yayoi period as upland settlements were built and many of such Sekizoku have been unearthed. It is thought from these circumstances that tools for hunting became weapons.

A human skeleton embedded many arrowheads were found inside the Kamekan (an earthenware jar-coffin) in the Yoshinogari Ruins. 10 arrowheads made from partially grinded stone, chipped stones, or shark teeth were embedded in the skeleton.

Process of making Sekizoku

Sekizoku were mainly made of obsidian, slate, or shale. Sekizoku belongs to flake stone tools. Picture shows a Sekizoku without a projection (Mukei Sekizoku), although there are Sekizoku that have a projection opposite the pointed top of an arrowhead and these are called Yukei Sekizoku (Sekizoku with projection).

Sekizoku during the Jomon period was produced by chipping an ore followed by sharpening it to the form of Sekizoku. The majority of Sekizoku belongs to chipped stone tools. The production of ground stone tools that involved the method of grinding the side of Sekizoku increased after the Yayoi period.

Attachment of Sekizoku to the shaft

It is thought that Sekizoku was attached to the shaft by tying it to tubulous plants in its hollow areas using string. For Yukei Sekizoku, it is thought that the projection was attached to the depression area to increase the strength. Moreover, asphalt was often detected on Sekizoku pieces found in the Tohoku and Hokkaido regions; thus, natural asphalt from oil mines in the Akita Prefecture is thought to be distributed throughout northern Japan by trade.

Sekisen (a stone harpoon)

There is evidence that Sekizoku was used as a fishing tool. Sekizoku is thought to be attached to the top part of a rotary-type separation head harpoon (a bone tool) when it was used as a fishing tool. However, chipped stone tools similar to Yukei Sekizoku, excluding its thick base (projected part) and poor construction, were seldom excavated. These are called Sekisen differentiated from Sekizoku. Sekisen are rarely found; therefore, many of its details including the usage, are not clear.