Past disasters may indicate that scientific knowledge is not necessarily incorporated in the decision-making process of disaster risk reduction (DRR). The 21st Technical Committee (TC21) of the Asian Civil Engineering Coordinating Council (ACECC) was established in 2016 to promote transdisciplinary approach (TDA). The TDA seeks for systematic organizational structures and processes that make all disciplines and sectors work together to make scientific knowledge become integral part of the decision-making process. The TC21 performed a session at the 2019 World Bosai Forum held in Sendai city, Japan. The presentations commonly touched on the issues of how to create and transfer new knowledge of DRR through the TDA. As a follow-up, the authors reviewed the presentations and studied the processes of creating new knowledge in terms of “modes and cycles of knowledge.” Two novel cases are presented in this article, for which experts of natural and social sciences teamed up to engage with the local communities to recover and/or enhance resilience. This article gives two main takeaways. First, one of the important commonalities of these two cases is the processes of externalizing the tacit knowledge, which refers to unrecorded experiences, feelings, and insight. Externalization is the crucial process without which the combination with the contemporary explicit knowledge would be difficult. Second, the new knowledge itself does not implement DRR. We need the know-hows to turn the new knowledge into action of DRR. A broad range of know-hows are required, such as establishing the organizational structures, funding schemes, and training programs. The future challenge, therefore, is to design a TDA that will integrate and implement these know-hows.