What is Muneoroshi in Japanese Katana terminology?

"Removing the ridge" or "Muneoroshi" (棟を卸す) refers to the process of making the ridge of the sword thinner while keeping the back of the blade, known as the "Shinogi", thick. This process is also expressed as "dropping the ridge", "shaving the ridge", or "stealing the ridge". When the ridge is removed, the cross-section of the sword becomes diamond-shaped, which structurally increases its resilience against forces from the side. Additionally, when cutting into an opponent, the smaller contact area reduces resistance, which improves the sword's ability to cut through. This highlights the strategic considerations and craftsmanship involved in sword making. The process of removing the ridge not only enhances the sword's resilience and cutting ability but also changes its aesthetic appeal.