The literature suggests two forms of flow slides: breaching and liquefaction. Both forms of failure have comparable ultimate circumstances. but the progression and sand movement mechanisms of breaching failure diverge from those of liquefaction. The first type. https://www.roneverhart.com/Traditional-Karate-Do-Okinawa-Goju-Ryu-Book-1-The-Fundamental-Techniques-by-Morio-Higaonna-Preowned/