筋--Direct translation "Tendon." Suji are lines in the hone, usually very straight like knife cuts. There are two type, "Living" and "Dead." "Living Suji" can negatively affect the blade, usually because the lines mark points where harder minerals have accumulated in the stone. These can be felt as a "click" on the blade when honing. "Dead Suji" are safe, they do not harm the blade, either because they are in a place that is easily avoided or, when honing, the honer has objectively tested and seen no harm.