Izaya's Knife

Izaya uses a switchblade (though it could also possibly be a folding knife or assisted opener) as a weapon of choice. Izaya is shown to have it hidden on his person, and is very adapt in using it. He is also shown throwing ordinary knives in the OVA.

History
Izaya is first shown using this weapon against the bullies harassing Anri, using it to cut and steal the purse of one of them. In almost all his confrontations with an offender, he is shown to use it as a means to defend himself. During High School, in the anime Izaya was shown using a regular 'kitchen' knife to cut Shizuo.