Rare knife money, city of Yi, ca.400-220 BC, "Warring State" period, Yan Kingdom under the Eastern Zhou Dynasty

Large archaic Chinese character Yi (also can be read as "Ming") /  Large archaic character Zuo (“left”) written retrograde (very rare variety). 140mm long, 16.12 grams. Hartill #5.b.

From an old US collection (comes with the original collection box) of Nathan Bower. Uncleaned