Niseishi is a wado ryu kata which translates as "24 steps". Shotokan people call it "Nijushiho".
It's not a kata that I spend a lot of time on, but we did have a play with it last night and I found it an enjoyable form to go through. It's a light, snappy kata with many good techniques (although the weird "punch him on the shin then tie his shoe laces together" technique half way through the kata needs some proper analysis!!)
The first sequence is particularly interesting - it involves pulling a opponent down while striking him, followed by a knee kick and a forearm or elbow smash down on the back of his head. That would upset anybody's day.
Other highlights of the form include low side kicks and a (kind of) mawashi uke at the end. It's the only "official" place (sigh...) in wado where you'll find this important technique. (That's partly why we include sanchin and tensho on our syllabus)
As for the rest of our training session I still believe that Naihanchi (Tekki Shodan in Shotokan speak) is the hardest kata in the world!