For the first 10 years that Semarang was a municipality, the city council took over the traditional markets with the help of an architect and urban planning expert from the Netherlands, Thomas Karsten (1884–1945), as an early step in managing the economic spaces in Semarang. This chapter looks at Karsten’s design for Johar Market, mainly at how he managed to slowly replace the race segregation by managing economic spaces to act as a public space. His idea to design the traditional markets as the city’s public spaces where anyone of any race or ethnicity could mingle economically had been rare in ethnically divided colonial societies. The chapter ends with the status of Johar Market today, which is not auspicious, but with an acknowledgment of the clear impacts of Karsten’s ideas even in markets today.