New information has been found on the man who changed Sengoku warfare forever. There is a link I found the data this morning that provided new details on Yanada Masatsuna.
Please see http://ameblo.jp/mikawa-hide/
and the date of his blog you should look is 7/9/09. Hide provides photos of Kunotsubo Castle and a links to maps as well.
Before Yanada Masatsuna received Kutsukake Castle as his reward for providing Nobunaga the intelligence that helped defeat the Imagawa at the Battle of Okehazama. It seems that Yanada came from Kunotsubo Castle. See Owada Tetsuo's Nobunaga Tettei Bunseki Junana Sho, p. 38.
In conclusion, Yanada Masatsuna started at Kunotsubo to Kutsukake Castle and cash.
Photos of Kutsukake Castle. The photo on the top is the ruins of Kutsukake Castle. The photo below is the Kutsukake Castle landmark. The most important historical fact was that Yanada Masatsuna's reward was bigger and better than Mori Shinsuke and Hattori Koheita combined.
I also added Hide's link to the link area.
Tenka no tame!