The 1928 zloty series was part of Poland's broader monetary stabilization effort under the Bank Polski, established only in 1924 to anchor the new currency after the catastrophic inflation that had destroyed the Polish mark. This tombac trial strike was never adopted — the production issue went to nickel — making surviving examples artifacts of the approval process rather than the mint's output.
The 1928 zloty series was part of Poland's broader monetary stabilization effort under the Bank Polski, established only in 1924 to anchor the new currency after the catastrophic inflation that had destroyed the Polish mark. This tombac trial strike was never adopted — the production issue went to nickel — making surviving examples artifacts of the approval process rather than the mint's output.