This Imperial German coin represents the 1st denomination coin of the Goldmark (1890). This particular example represents the final production poi to WWI (1914-1918). Due wartime demand, the 1 Pfennig was debased mid-war. Replaced by a design made aluminum, which was issued to the war's end. It was abandoned by the succeeding Weimar government.
Notably coin is a smooth-edged design made of a copper and weighs 2 g. Its dimensions are 17.5 mm (0.69 in) wide and 1.35 mm (0.045) in thick. Making it slightly smaller in size than a US Penny (19.05/0.75 in), in that respect.
Observe
The observe is practical in it's design, featuring a large number "5" at its center. This number "5" simply represents the coin's 5 Pfennig value. As supported by the lower portion of the coin's warp-around text. The upper section reads "DEUTSCHES REICH 1913" (German Empire). Listing the coin's issuing nation and mint year.
A pair of dimples separates the upper and lower portions of the warp-around text.
Reverse
The reverse depicts the Reichsadler, the symbol of Imperial Germany. Notably the coin uses a small shield design, this style is known as a Type II. This design was copied by the later aluminum variants issued, after the mid-war debasement.
Unlike some later coin's issued during WWI, this coin utilizing mintmarks. These mint marks are represented by a pair of letter "A"s, located below the eagle's tail. This letter "A" identifies the coin as a Berlin-minted coin.
Additional Notes
The 1 Pfennig was produced by the Berlin (A), Munich (D), Muldenhütten (E), Stuttgart (F), Karlsruhe (G), and Hamburg (J) mints.
Despite being last issued in 1916, the 1 Pfennig was not demonetized until 1 March 1942.
During WWI coin shortages lead to the introduction of Kriegsgeld (war money) coins.
Kriegsgeld was only redeemable for standard currency, after a set period after peacetime.