I once asked a martial artist what he thought of Ninjutsu and was surprised when he said "weapon specialist" But I think its very true. No other martial arts has such a varied amount of weapons and tools as Ninjutsu. Perhaps kung fu also has a wide range of unique weapons. But Ninjutsu has weapons and tools. and sometimes tools are used as weapons. it is these special weapons and tactics that make ninjutsu unique to other martial arts. Ninjutsu has a huge array of skills. not just a huge variety in Taijutsu and weaponry but also traditionally depending on specific Ryu proficiency in the field survival, horse riding, military strategy, stealth etc was included this is not typical of today's martial art that mainly focus on one thing like unarmed. or one weapon like sword. Is it this huge variety of skill sets that make Ninjutsu different to other martial arts. is this because Ninjutsu is more of a specialist martial art that teaches unconventional tactics and weapons? for example I don't think Shuko was a common weapon and I doubt it was taught to the standard warrior class but it is a part of koto ryu weaponry and is also a tool for climbing. and is perhaps why there is a lot of hand claw strikes in their Taijutsu. is this what makes Ninjutsu stand out and be unique compared to other martial arts?