About this note

• 20 Baht - Rama X (Series 17; paper) ND (2018). 
  
• Front: King Vajiralongkorn in Air Force uniform. 
  
• Back: Green on yellowish orange. King Rama I and King Rama II, Grand Palace, mural of a scene from Panji tales, Trishula trident in Chakra on guillochés. 
  

• Origins of the Thai state trace to the Sukhothai kingdom of the 13th century and the later Ayutthaya kingdom (14th–18th centuries). Modern Thailand begins with the Rattanakosin era founded in 1782, after Ayutthaya’s fall, when the new capital was established at Bangkok and the Chakri dynasty commenced.
• Thai monarchy (brief history) has remained continuous under the Chakri dynasty since 1782; it moved from absolute authority to constitutional rule after the 1932 revolution. The monarchy has acted as guardian of Buddhism, anchor of national symbolism, and patron of arts, architecture, and modernizing reforms across the 19th and 20th centuries.
• Thai currency (baht) evolved from the pre-modern silver tical system into a decimal baht under Rama V’s reforms. The modern baht is issued by the Bank of Thailand (founded 1942), with banknotes typically combining portraits of the reigning king with episodes from earlier reigns, state institutions, scientific achievements, and dynastic emblems such as the Trishula-in-Chakra.
• Thai alphabet developed in the 13th century from Old Khmer script. It is an abugida with 44 consonants and a tone system encoded through consonant classes, diacritics, and orthographic conventions that preserve historical sound patterns.
• Thai cuisine’s international fame rests on its balanced sweet–salty–sour–spicy palate, the integration of Chinese techniques, refinement from Bangkok’s royal court, and strong regional diversity in Isan, Lanna, Central, and Southern traditions.

Kings of Thailand

• Rama I (Buddha Yodfa Chulalok) founded the Chakri dynasty, rebuilt Siam after Ayutthaya’s destruction, established Bangkok as the capital, began construction of the Grand Palace, and restored classical literature and Buddhist institutions.
• Rama II (Loetla Nabhalai) presided over a flourishing of poetry, court arts, and literary refinement during the early Bangkok period.
• Rama III (Nangklao) expanded trade with China, commissioned temples with Chinese architectural influence, and strengthened Siamese authority in Laos and Cambodia.
• Rama IV (Mongkut) modernized religion and statecraft, introduced Western astronomy, accurately predicted the 1868 solar eclipse, and promoted scientific engagement symbolized by the Khao Wang observatory and celestial imagery.
• Rama V (Chulalongkorn) abolished slavery, modernized the administration, built railways and postal systems, and traveled extensively in Europe, including the visit to Notodden, Norway, where he met industrialist Sam Eyde.
• Rama VI (Vajiravudh) advanced Thai nationalism, modern literature, and civic identity; he founded the Thai Boy Scouts in 1911 and cultivated a modern military image represented in mounted portraits.
• Rama X (Vajiralongkorn) appears on all Series 17 notes in Royal Thai Air Force uniform, reflecting his long military training and the contemporary ceremonial identity of the dynasty.

Other Items Portrayed

• Chinese junk — emblem of thriving Sino–Siamese maritime trade during the reign of Rama III and of the strong Chinese influence on Bangkok commerce and architecture.
• Khao Wang observatory — Rama IV’s astronomical site in Phetchaburi used for eclipse calculation and evidence of the king’s integration of Western science.
• Orion Constellation — reference to Rama IV’s scientific expertise and his internationally noted eclipse prediction. The eclipse occurred on 18 August 1868, visible as a total eclipse across the Gulf of Thailand and southern Siam. Rama IV calculated its timing and ideal viewing location using Western astronomical tables and geometry learned during his years as a monk. He selected Wakor in present-day Prachuap Khiri Khan, positioned exactly on the path of totality; his prediction proved exceptionally accurate for the era. He invited European scientists and diplomats, including French and British teams, creating one of Southeast Asia’s earliest international scientific collaborations. Western astronomers praised his precision; Emmanuel Liais noted he possessed “the mind of a true European savant.” He used the eclipse to show that Buddhist cosmology could coexist with scientific cosmology, easing acceptance of modern knowledge within traditional Siam. The site was mosquito-infested; Rama IV and his son (Rama V) contracted malaria, and Rama IV died six weeks later, making the event both triumph and tragedy. The eclipse bolstered the monarchy’s reputation as rational, modern, and scientifically competent, strengthening Siam’s diplomatic standing with colonial powers. It embodied the Chakri dynasty’s strategy of selective modernization—adopting Western science and diplomacy without ceding sovereignty. Modern Thai astronomy commemorates the event; Wakor remains marked, and Rama IV is often honored as the “Father of Thai Science.”  In 19th-century Thai astronomy, Orion’s Belt (ดาวไถ / Dao Thai, “the plough”) served as a key reference constellation, widely recognized and culturally embedded.

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