[Gustav]

Alan, I see you have done your homework and read the article by Jimmy H. This article, its BI twin and at least one website with information allegedly provided by Djeno himself is, let's say it politely, not always following the Western style "objective reality". A blatant example is the 1940 thing, which most probably is based on an unbelievable misreading and combination of two passages in an article on Djeno by Linus Suryadi from 1990:

After death of Empu Yosopangarso in middle of 80ties "Sedangan dua kakaknya yang lain, Genyo Dihardjo dan Wignyosukoyo, tidak melanjutkan tradisi warisan tersebut karena alas-alasan yang bersifat primer, langka pemesan, ongkos pembuatan tinggi, dan pekerjaan berat."

And "Selama kurang lebih 30 tahun antara 1940 sampai 1972 kehidupan Jeno Harumbrojo selaku empu keris praktis mandeg. Hal serupa tentu saja juga dialami kakaknya Yosopangarso, almarhum."

Which becomes "Djeno membuat keputusan ini setelah saudaranya, Empu Yosopangarso, meninggal pada tahun 1940, diikuti oleh kematian saudara laki-lakinya yang lain, Genyo Dihardjo dan Wignyo Sukoyo. Pesanan keris yang makin sedikit, ditambah biaya bikin keris teramat tinggi untuk ukurannya, membuat niatnya bulat untuk berhenti menempa keris."

This is how history is written.

The same can be said about IFICAH information that Yosopangarso was Djeno's uncle.

Yosopangarso clearly is the eldest brother. On old pictures from 70ties with subject of smithing we see Yosopangarso, Djeno, Genyodihardjo and Wignyosukoyo, so I think, we can say, at some time all brothers were involved in smithing (at least as spectators). Solyom writes "three of the sons (...) had once helped their father make keris.", which is something different.

As I understand, all information about Keris from 1945 comes from Friedrich Seltmann, who visited Empu Supowinangun and his sons in 1962. He nowhere explicitly mentions particularly Djeno's help in making this Keris. Interestingly, Seltmann provides a picture of a drawing of three Keris with three different Dhapur and three different Pamor from 1962, made by Yosopangarso, and Yosopangarso's name in family lineage is Yosocurigo.

Empu Supowinangun died in 1963 (or 1967), and there have been hints that the 1945 Keris (if it exists at all) wasn't the last Keris made by Empu Supowinangun together with his sons.

The maker of 1974 Keris was Yosopangarso, of course with Djeno involved in the process.

It would appear that prior to the involvement of Dietrich, none of the Djeno family were actually working as smiths, it was Dietrich who got them up & working with fire & iron again. - they did not make any Keris or Pamor work, but Yoso still was a blacksmith at the time Dietrich Drescher arrived, his brothers helping him.