100 Piso Seal type 4

The Seal type 4 designation marks a specific phase in the BSP's gradual redesign of its official seal during the Aquino and Ramos administrations — a bureaucratic detail that created a collector-distinguishable subtype within what is otherwise a long-running series. The transition from black to red to blue serial numbers across five signature combinations makes date-attributing individual notes surprisingly precise, given that the printed date range spans six years.

The Security Plant Complex has produced Philippine banknotes in-house since the late 1970s, one of the few central banks in Southeast Asia to maintain fully domestic production at this scale. The Ramos & Cuisia blue serial examples are the latest in the sequence and typically the easiest to source.