CP conservation and violation in neutral kaon decay are considered from a first principles’ theory, recently published as “Scalar Strong Interaction Hadron Theory”. The arbitrary phase angle relating K0 and 0 in current phenomenology is identified to be related to the product of the relative energy to the relative time between the s and d quarks in these kaons. The argument of the CP violating parameter ? is predicted to be 45? without employing measured data. The K0S decay rate is twice the K0L -K0S masss difference, in near agreement with data, and both are proportional to the square of the relative energy 29.44 eV. Any pion from K0L decay will also have a mass shift of ≈1.28 × 10-5 eV. The present first principles’ theory is consistent with CP conservation. To achieve CP violation, the relative time cannot extend to both +∞ and -∞ but is bounded in at least one direction. The values of these bounds lie outside the present theory and it is unknown how they can be brought forth. -B0 mixing is also considered and the relative energy is 663.66 eV.