The postage stamps issued by the old German state of Bavaria between 1867 and 1878 hold significant historical and philatelic value, particularly the rare and well-regarded stamps featuring Bavaria’s coat of arms. Stamps from this period are highly collectible due to their rarity, aesthetic appeal, and the unique Bavarian history they represent, especially as they were produced before Bavaria integrated into the German Empire.

Among these stamps, the **18 kreuzer pink unused (postfrisch)** stands out as one of the rarest and most sought-after. Issued in a delicate pink shade, this stamp was valued at 18 kreuzer, the Bavarian currency before its transition to the mark system in 1871. Its scarcity can be attributed to limited production and its delicate color, which has often faded or deteriorated over time. Finding a well-preserved, unused 18 kreuzer stamp today is a remarkable discovery for collectors. Its design, featuring Bavaria's intricate coat of arms, is an exquisite reflection of the region’s pride in its independent identity. Collectors value not only its rarity but also its vivid connection to Bavaria’s pre-unification history.

Another stamp of note from this era is the **40 pfennig yellow, also unused (postfrisch)**. Issued after the German currency transition, this stamp illustrates the economic and cultural shifts Bavaria underwent during this period. The 40 pfennig yellow stamp is distinguishable by its bright, eye-catching color and high-quality printing. Because of its distinct color and the relatively small number issued, it is one of the most treasured pieces from the time. This stamp is relatively rare in mint condition, adding significantly to its allure among collectors.

Lastly, the **50 pfennig brown, used (gestempelt)** stamp is also highly valued. Although it’s not as rare as the 18 kreuzer pink or the 40 pfennig yellow, its worth lies in its historical significance and aesthetic appeal. The deep brown color, combined with a fine cancel mark, makes it a beautiful example of Bavarian philately. These used stamps provide insights into Bavaria’s postal history, offering a snapshot of the era’s mail routes and usage patterns.

Each of these stamps—the 18 kreuzer pink, 40 pfennig yellow, and 50 pfennig brown—illustrates a unique aspect of Bavarian history and the elegance of early stamp design. Collectors treasure them not only for their rarity but also for their connection to the distinctive heritage of Bavaria before its full integration into a unified Germany.