N-gauge Japanese-style Model Train
I have purchased and just received this CY700001 2set 1/700 Scale Model Ship 0.55mm Black Anchor Chain.
It's meant for a model ship but I think I can use it to build a fence similar to this https://www.sunpole.co.jp/supply/post-8159/
The chain link diameter is 0.55mm = prototype 82mm. Maybe a bit large, but should be ok.
By the way, if you are looking for examples of different types of fences, there are 100 pages of photos in the landscape catalog here: