The work of William de Lange is highly recommended. He produced this short documentary series to accompany his book 'A Life In Arms'. Update 2019 - people can now view the author's comprehensive website dealing with Musashi here .
A free PDF can be found here - I have only provided a link to the location of the file as I have not been able to determine whose work this is or the copyright status. If you know anything about this document please let me know in the comments. The translation I most prefer is that of Tokitsu .
The following links show some examples of art attributed to the man himself: Kampaibudokai here . MusashiMiyamoto.com here . Trangsformation blog here .
Some interesting notes from Kampaibudokai can be found here . There are 5 two sword kata. 1 chudan 2 jodan 3 gedan 4 waki gamae (hidari) 5 migi waki gamae
Interesting notes on the kata from Kampaibudokai can be found here . There are seven short sword kata. 1 sassen 2 chudan 3 uke nagashi 4 moji gamae 5 haritsuke 6 nagashi uchi 7 aisen
There are twelve long sword kata. You can find some interesting notes on the kata from Kampaibudokai here . 1 sassen (sashi sen) 2 hasso hidari 3 hasso migi 4 uke nagashi hidari 5 uke nagashi migi 6 moji gamae 7 haritsuke 8 nagashi uchi 9 tora bura 10 kazuki 11 aisen uchidome 12 amashi uchi
Most streams of Niten Ichi Ryu contain: 24 Kenjustu kata made up of - 12 long sword - 7 short sword - 5 two sword 20 Bojutsu kata (rarely seen) made up of - 7 Bo vs Bo - 13 Bo vs Sword Different streams also contain various Oyo-waza, although information is scarce - the exact makeup varies between groups. - Jitte (6) - Aikuchi (Roppo) (5or 6) (dagger without guard/Jujutsu) - Sessa? (5) (no idea what this is, possibly a tool or Jujutsu)