5 Baht Series 9 Type I 'Red Serial'

Thailand's Series 9 notes were introduced following the 1947 military coup that ousted the civilian government and eventually restored the monarchy's prominence under Bhumibol Adulyadej. The 5 Baht in this first type carries red serial numbers — a detail that distinguishes it from the later black-serial Type II issues of the same design, and the primary reason collectors treat them as separate catalog entries despite identical artwork.

De La Rue printed the series in London at a time when Thai domestic printing capacity was still limited. The red serial variant is the scarcer of the two types.