wiki- Machi

• Definition: The small step or gap found between the blade and the handle of a Japanese knife, serving structural, functional, and aesthetic purposes.
• Details: Machi is positioned between the ago (heel corner of the blade) and the nakago (tang inside the handle). Its presence and size differ depending on the knife type—yanagiba and usuba often feature a visible machi, while deba and nakiri generally show little or none.
  
• Comparison: In Western knives, blade length is typically measured from bolster to tip, while in Japanese knives it is measured from the machi to the kissaki (tip). This distinction means a “210 mm” yanagiba with a machi may have a shorter exposed edge compared to a Western counterpart of the same nominal size.
  
• Practical Use: Machi contributes to durability and balance by reinforcing the connection between blade and handle. It also absorbs some stress during use, preventing cracking or loosening. Additionally, the presence of machi allows more precise re-handling or replacement of handles.
  
• Cultural Note: Beyond function, machi is an aesthetic element in fine Japanese knives, often finished with care by the craftsman. Its subtle presence is appreciated by connoisseurs as a mark of authenticity and traditional construction.

Related websites
Parts of a Japanese Knife