Seal Script

I know this is a long shot, but does anyone have any idea what is written on this habaki of this tantō I've bought? I think it's 'seal script' so I understand it's likely indecipherable.

Perhaps @Toritoribe -san or @Majestic can assist further?

Yes, its a kind of seal script. The two halves form one zen phrase, but the first part is the most famous/referenced. The photo on the bottom should be the first line of the idiom/phrase, and the photo at the top should be the second line:

松無古今色
竹有上下節

New or old, the pine's color doesn't change,
The bamboo has nodes on the top and bottom.

The first phrase is intended to represent the timelessness, or unchanging nature of the universe.
The bottom phrase has a different nuance, and is meant to illustrate that even as a bamboo stalk is made of parts that have connecting ridges on the top and bottom of each section of the stalk, they all form the whole. In other words, both top and bottom (high and low, rich and poor, etc.) form the whole.

There is a good English explanation of this idiom at the Reddit link below

Wow that's amazing! Thank you so much, majestic. I never thought it could be translated!

Very cool habaki. What does the tantō and the rest of the fittings look like?

It in shirasaya and it's a yoroidoshi (armour piercer) since it's thicker than the usual tantō.

• Blade length: 35.4 cm
• Curvature: 0.5 cm
• Number of Mekugi hole: 2
• Motohaba: 32.3 mm
• Motokasane: 4.6 mm
• Signature: No signatur
• Era: Shinshinto
• Structure: Hira-zukuri, Iori-mune
• Jigane: Itame
• Hamon: Togariba
• Boshi: Midarekomi
• Weight(blade only): 410 g
• Nakago: Ubu
• Original Registration No.: Kyoto 61577