The  Nunchaku  (ヌンチャク) or  sosetsukon is the most famous Kobudo weapon. It has been popularised by Bruce Lee movies in the 80s.
Nunchaku is a derivative of threshing flail or aderivative of horse’s bit. It is made by 2 red oak sections connected by a  cord. The sections can be octogonal (Okinawa) or rounded (China).

The cord between the two sections is placed using a very specific node called Okinawan node.

Okinawa Node

This weapon is very dangerous to be used (some practitioners are using an helmet during the first sessions).
Nunchaku is reserved for well experienced kobudoka and is required for Black Belt testing (Shodan).

Katas (カタ) :

Nunchaku dai ichi
Nunchaku dai ni

Video of nunchaku dai ichi kata  :