(a) Distribution of orbital periods and mass ratios of short-period DNe: 9 with P_orb shorter than the period minimum (large squares and black arrows), 34 WZ Sge-type DNe from T. Kato (2015; dots with error bars), and three period bouncer candidates with P_orb greater than the period minimum (large pentagons). For KSP-OT-202104a (red dashed line), we show the superhump period (the orbital period differs from the superhump period by ∼1%, usually being shorter but occasionally longer) and the mean (q = 0.078) and standard deviation (0.017) of the mass ratio values for the known WZ Sge-type DNe from T. Kato (2015). Data for the first group and KSP-OT-202104a are from Table 3. The colors for the second group of WZ Sge-type DNe represent their types: A (blue), B (green), C (orange), D (red), E (purple), and unknown type (black). The third group of period bouncer candidates consists of EG Cnc (P_orb = 0.060 d, q = 0.048; M. Kimura et al. 2021), GOTO0650 (P_orb = 0.063 day, q = 0.05; T. L. Killestein et al. 2025), and QZ Lib (P_orb = 0.064 day, q = 0.040; A. F. Pala et al. 2018). The orange dashed and green solid curves show the standard and optimal evolutionary tracks of DNe, respectively, from C. Knigge et al. (2011). The blue vertical dotted line indicates the period minimum (∼76 minutes; Y. Lee et al. 2024). (b) Histogram of the orbital periods for the WZ Sge-type DNe. (c) Histogram of the mass ratios for the WZ Sge-type DNe. For panels (b) and (c), DNe known as the WZ Sge type (CSS 130418, ASASSN-15po, EG Cnc, and GOTO0650) are included; KSP-OT-202104a is not.