In 1898, Germany launched the Deutsche Tiefsee-Expedition (German Deep Sea Expedition). The purpose of the Expedition was to conduct oceanographic and biological studies off of Antarctica and in the Indian Ocean.
Route of the Expedition
The Expedition traveled via the Valdivia, a steamer formerly of the Hamburg-America line.
The Valdivia arrived in Kamerun in late September 1898, and departed in early October. Due to the unusual volume of mail being sent by the members of the Expedition, the post office in the city of Kamerun (present-day Douala) ran short of 10 Pf stamps. To remedy the shortage, the postmaster bisected 20 Pf stamps for use as 10 Pf provisionals. As with other provisional uses throughout the German colonies, this practice was frowned upon, but tolerated by the German postal authorities. The bisects became known as the Valdivia Provisionals.
All legitimate uses are canceled on 3 October 1898. The total number of stamps bisected is unknown, but is believed to be approximately 100 (1 sheet). It's among the rarest of the German colonial bisects, third in catalog value (€20,000) only to two of the three bisects from the German Marshall Islands (MiNr 3 I H at €35,000, and MiNr 12 H at €45,000).