  This chapter provides an in-depth analysis of the properties and phenomena
associated with neutral K-mesons. Kaons are quantum systems illustrating
strange behaviours. We begin by examining the significance of strangeness and
charge parity violation in understanding these particles. The concept of
strangeness oscillations is then introduced, explaining oscillations between
$K^0$ and $\bar{K}^0$ states. The regeneration of $K_S$ is investigated,
uncovering the underlying mechanisms involved. The discussion moves on to
quasi-spin space, exploring its bases and their implications. The entangled
states of kaon pairs $(K^0,\bar K^0)$ are considered, with a focus on maximally
entangled neutral kaons and non-maximally entangled states. Decoherence effects
on entangled kaons are examined, utilizing the density matrix description to
capture the dynamics. A dedicated decoherence parameter is introduced to
quantify the impact of decoherence. Furthermore, the chapter investigates the
loss of entanglement through measures such as Von Neumann entanglement entropy,
entanglement of formation, and concurrence. These measures provide insights
into quantifying and characterizing entanglement in the context of neutral
kaons. Through this comprehensive exploration of properties, phenomena, and
entanglement dynamics, this chapter aims to pointing out recent works on
neutral kaons, contributing to advancements in particle physics.
