Typically, our clothes are cut along the grain of the fabric vertically or horizontally. It provides better stability since it aligns with the direction of the fabric's threads. The bias cut is the technique of cutting on the diagonal grain (at 45 degrees) of the fabric rather than the straight and cross grains.
Pros
It offers flexibility, achieving a natural harmony with the body. While it seems snug, it leaves space, allowing movement within the garment's natural shaping. It works well with fabrics like silk, chiffon and georgette, enhancing their drape.
Cons
Because of the way it is cut, it consumes more fabric and be more sewn seams in the final product, and the scrap is higher due to its more difficult patchwork and hemming. So bias cut clothes is usually more expensive.
Influential figures
Madeleine Vionnet: The pioneer of bias cut, emphasizing the natural curves of the female body, opposing tight-fitting garments. Vionnet's bias cut technique maximizes the fabric's stretch and flexibility.
John Galliano: Known for his strong utilization of bias cut, it became a signature element in his designs. Combining extreme romanticism with curve-enhancing aesthetics, he adeptly blends bias cut with sheer fabrics, showcasing graceful lines and sensual contours.
Just straight out your garment and carefully observe the direction of the grain/threads. If they are diagonal, it indicates the bias cut.