Ah - yes, "10-speed" doesn't mean what it used to mean. These days it means "ten speeds in the back", which is possible only because of the much narrower spec for chain and sprockets.
What you need is currently known as an "8-speed" chain.
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1987 Nishiki Prestige (now 650B!)
1981 Trek 710
198? Nishiki Olympic 12 mixte (now 650B!)
2020 Surly Troll fat-tire build