Quantum oscillations in the centrosymmetric skyrmion-hosting magnet <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>GdRu</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Si</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>

The skyrmion formation mechanism in centrosymmetric systems remains to be understood, partially because of the lack fundamental understanding electronic structure. authors observe de Haas--van Alphen and Shubnikov--de Haas oscillations high magnetic fields up 58 $T$ on GdRu${}_{2}$Si${}_{2}$, which is one such skyrmion-hosting magnets with shortest diameter ever found. Combined first-principles calculations, now reveal structure GdRu${}_{2}$Si${}_{2}$ its reconstruction at phase boundary.