Some more info from another source, the Koza (thanks to AFU, sorry for the poor picture) to support the 3 generations matter :
SURUGA NO KUNI 駿河国
Shida-gun Shimada-shi of this kuni is a town on the left bank of the Ôigawa (Ôi River), and here a
tôkô group founded by SHIMADA YOSHISUKE 島田義助 prospered. SURUGA 駿河 is a place
which has deep relationships with the great clans of the Imagawa, Takeda, and Tokugawa. In the late Muromachi Jidai, there was especially vigorous activity shown by these three, but a story can be seen in
the SUN TÔ ZU KAN 駿遠豆鑑 (SURUGA 駿河, TÔTÔMI 遠江, and IZU 伊豆 Taikan) which says that YOSHISUKE 義助 obtained the favor of Imagawa, and it is said that the YOSHI 義 of YOSHISUKE 義助 is a ji that he received from the name of IMAGAWA YOSHITADA 今川義忠.
I think this is a story which should be believed. At one time a long time ago there was a tendency to overlook the founder of this YOSHISUKE KE 義助家, however, in actuality, he is thought to be a smith in his prime of sword making around KÔSHÔ 康正 (1455-1457). Even if he is moved back
earlier, this would probably be to around EIKYÔ 永享 (1429-1441). This is the jidai assumed according to common knowledge of sword observation.
A pamphlet was published in October 1962 by sword lover Matsushita Masahika (or Shôji) Shi of Shizuoka-ken entitled "Shizuoka Meitô Monogatari" (Tales of Famous Swords of Shizuoka). Present in this is detailed local research in regard to YOSHISUKE 義助 and his extended family. As for the investigation of the tôko, kinkô, and tsubakô of each locale, these had been done for some time by local people, and fulfills the greatest wishes of this writer. I would ask for anyone who desires the details to please consult this same pamphlet.
According to that pamphlet, the family name of the YOSHISUKE KE 義助家 was GOJÔ 五条 , and the Myôô-Yama Chôtoku-Ji is their family temple. It is said that this temple came to moved from Shimada-chô Go-chome around 1912, an since the old tomb markers were naturally renovated, it is probably difficult to hope for accuracy, but it seems that there are people who are doing further research locally.
…OMISSIS…
KEIZU OF SHIMADA YOSHISUKE KEI
YOSHISUKE 義助: Around KÔSHÔ 康正 (1455-1457). [TN]
YOSHISUKE 義助: Around EISHÔ 永正 (1504-1521).
YOSHISUKE 義助: Around TENMON 天文 (1532-1535).
HIROSUKE 広助: Around KÔJI 弘治 (1555-1558).
KUNISUKE 国助: Around TENSHÔ 天正 (1573-1592).
TERUYOSHI 輝吉: Around KÔJI 弘治 (1555-1558). He also inscribed HIROSUKE 広助.
TERUSUKE 輝助: No remarks.
SUKEMITSU 助光: No remarks.
YARI
Mei: YOSHISUKE SAKU
(OTEGINE NO YARI お手杵の槍)
Length: 4 shaku 6 sun (about 139.4 cm)
槍 銘 義 助 作