In this work, I assess the risk of underwater Joense. This is the first analysis of underwater Joense risk based on the information of all Joense contracts. Using the house price change rate distribution condition on the house price index change, I measured the risk of underwater Joense on various house price scenarios. My results show that the risk of underwater Joense is highest in the first half of 2024. If house price index falls 0%~10% (20~30%) yearly, 8.8% (22.0%) of the apartments is expected to experience underwater Joense. The result of this research can be utilized in financial institution's risk management.