Can anyone read the signature on this blade?

[gtbpappy]

Blade

[GHP]

It looks like:
誠 兼国鉄之

Makoto Kanekuni Tan wo
[With Sincerety] Kanekuni Forged This

Makoto 誠 is a given name and should follow the family/art name; however, here it is placed before the smith's art name, so I think it means "with sincerity" or "Sincere."

I think 鉄 [tetsu/ iron] is probably shorthand for 鍛造 tanzou [forge] and/or 鍛練 tanren [to forge].

I found an entry for Kanekuni, but don't know if it's the same man. He worked for Horii Taneaki [my mother-in-law's relative]

V. Hanazawa Tanren Jo (羽沢鍛練場) and the Horii (堀井) Group

The Hanazawa Tanrenjo was opened in the late Meiji period and operated until the late Taisho period. The following list includes smiths from the Hanazawa Tanrenjo and their students:

1. Horii Taneyoshi (胤吉) / Yoshiaki (吉文)
1.1. Horii Taneaki (胤明)
1.1.1. Horii Toshihide (俊秀) / Kaneaki (兼明) / Hideaki (秀明)
1.1.2. Kurihara Akihide (昭秀)
1.1.3. Masakuni (真国) / Nobuaki (信明)
1.1.3.1. Masayoshi (正義) / Sukeyasu (祐康)
1.1.3.2. Sukehiro (祐弘) / Sukemitsu (祐光)
1.1.3.2.1. Suketsune (祐恒) / Sukekuni (祐国) 1.1.3.3. Kuniyoshi (国芳)
1.1.3.4. ? (藤田五三郎)
1.1.4. Sukekuni (祐国) / Toshiaki (寿明)
1.1.4.1. Tsuneyasu (恒康)
1.1.4.1.1. Suketsune (祐恒) / Sukekuni (祐国) 1.1.4.2. ? (池田？吉)
1.1.5. Kanekuni (兼国) / Yoshiaki (良明)
1.1.5.1. Kanekuni (兼国) / Masahira (真平)
1.1.5.1.1. Kanekuni (兼国)

source

Here's another couple, but no images of their work:

Kanekuni
兼國
Seki Ogawa, Gunto
1938

Kanekuni
兼國
Kato, Gendai,
Showa


--Guy