During the Bronze Age, the swords found in Japan were very similar in shape to those found in continental Asia, i.e., China or Korea, and the Japanese adopted the Chinese convention for sword terminology along with metallurgy and swordmaking technology, classifying swords into the (either straight or curved) single-edged variety called tō 刀 and the (straight) double-edged variety called ken 剣. There is some small overlap in that there were some double-edged curved swords such as Tulwars or Scimitars which were called Tō, because the curvature meant that the "front" edge was used in the overwhelming majority of instances.