To improve an assembling technique for investment casting core.

The investment casting pattern is formed by forming a metal-made first core element including at least one recess. The first core element is engaged with at least a mating one of an element of a die and a second core element. The recess serves to retain the first core element relative to the mating core. The die is assembled and a sacrificial material is introduced to the die so as to at least partially embed the first core element. The recess can be preformed prior to cutting the first core element from a larger sheet of material.