O is an exploration of Osaka’s waterfront by Daniel Reuter and Umihara Chikara, created during a month-long shared residency in the city. Staying in a narrow house overlooking the Okawa River, the two artists embarked on daily walks and travelled to the vast industrial zones next to the bay. Every photograph in the book was taken during this period; each artist contributed half, though it remains deliberately unclear who produced which image. In the city’s evolving periphery, the forms of global infrastructure meet the slower, subjective pace of lived experience. The book appears as part of the artistic programme of the Luxembourg Pavilion at the Osaka World Expo 2025.