Lebanon
1957-?

The jury is still out as to why this pattern was applied to the rear of mint stamps, over the gum, although the need to identify post offices' stocks of stamps from those stolen during periods of civil unrest/war occurred more than once during Lebanon's turbulent history.
Clearly the main concern was that the stolen stamps would find their way into the hands of dealers and then collectors, as mint items. The applied linear pattern is not easily visible on used items off-piece, and detection of stolen stamps used on mail would have been almost impossible even if envelopes were held up to a strong light.
A later method - used in 1978 - was to apply a security "grill" pattern to the face of remaining stocks, (although there may have been some mint stamps obtained legally prior to the theft, which would be indistinguishable from stolen items).
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