SteveM

謹作高山刀　　　Kinsaku Takayama-tō (Diligently made Takayama sword) 刀匠　服部正廣　Tōshō Hattori Masahiro (Smith: Hattori Masahiro) 研師　伊藤六助 Kenshi - Itō Rokusuke (Polisher: Ito Rokusuke) Its nearly identical to the signature that Dave posted, except for the polisher.

Polisher is 伊藤六助 - Itō Rokusuke

Looks like the loop is a kaō that belongs to the tester. I couldn't find any other samples of this tester's work, so I can't say with conviction, but yes it looks like it should be Yoshizane's kaō

三ツ胴重裁断之 Mitsudō kasane saidan kore 貞享五年戊辰十月十三日　鵣飼十郎衛尉義真 Jōkyō go nen tsutinoetatsu jūgatsu jūsan-nichi Ukai Jūrōe-no-jō Yoshizane Three body cutting test 1688, October 13th. Ukai Jūrōe-no-jō Yoshizane Presumably this is Ukai Juroemon who is a well-known tester. I don't know why his name is missing one of the kanji here (門).

I'm not 100% confident that it is indeed 写 (or 寫) but the single kanji coming after the kao is pretty unique. I don't think its a name. I thought the kao would be the actual smith's kao, and 写 would be his acknowledgement that the blade was an attempt at emulating a certain style or another smith.

Oops, yes that's what I meant. Utsushi.

kao + 写　(utsuri)

There are all kinds of #5s. Take a look at the variation on the page below https://moji.tekkai.com/zoom/五/page.html

津田越前守助廣 Tsuda Echizen-no-kami Sukehiro

Looks to me like either Z三五四 or 乙三五四 Z354 or 乙354 (乙 is a used in numbering or ordering things. Both Z and 乙 would just be part of the assembly number). At any rate, the 354 is a match for the tang and the tsuka.

Yes, Saitō Kiyoshi (斎藤清)

Polishing, specifically "shinogi-zukuri" polishing. It says in the English description too. "Our staff member, Yoichiro Kawakami, placed 6th in the Excellence Award! This was his first serious attempt applying to this competition in the area of sword polishing."

上等小柄六本 Jōtō kozuka roppon 6 high quality kozuka I can't make out the 6 lines under that, but they are describing the 6 kozuka: material/theme Third from right is "Shibuichi, tori (bird)" The first and fifth from the right might be 赤銅 (shakudō) then a description of the theme

赤坂町一　Akasaka Chōichi (various readings) 髙橋熊次郎 Takahashi Kumajirō (name, there was a politician in the mid-20th century with this name).

Too dark for me. But I think even with a sharper, brighter picture, it would be a tough one. Possible to get a better picture?