Hi,
Wich Tada?
祇 - 矩 - 兄 - 周 - 但 - 旦 - 忠 - 偵 - 田 - 土 - 督 - 妙 - 矢 - 亘 - 尹 -
I personally don't find one (it's true that i've old eyes :D)
I have also checked the Yoshitada smiths, i've found 2, one in Enpo -Tenna (oshigata) and one in Genroku; both use this kanji 忠
Edit,
There is a third Yoshitada in Showa era, a sword with the mei Hizen Kuni Yoshitada and dated from 1945 is extant.