Swedish Flag Day seals were first issued for 1916-17 and since 1918 have been issued annually. The seals usually bear the text "Svenska Flaggans Dag" or "Stiftelsen Svenska Flaggan" or "Nationaldagen". They are colorful, patriotic, and often great works of miniature art. For a few of the years matching picture post cards also exist. Because most years do not indicate the year of issue, the seals can be difficult to identify without an illustrated catalog (such as this website). This is the only on-line illustrated listing of them of which I am aware. The early issues are generally scarce, some very scarce, and some of the modern issues, from the 1960s onward, can be frustratingly difficult to find. Used examples are quite scarce and seals used (tied by postmark) on cover or card are extremely scarce.
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