This craft essence is currently unavailable on the EN ver.Seaside Luxury is can be purchased from Dead Heat Summer Race! event shop.
Here is a list of servants & CEs that can be obtained for the duration of the Summer 2017 event part 1: Dead Heat Summer Race and part 2: Death Jail Summer Escape.
Rashoumon event (Ibaraki Douji event)
Murder at the Kogetsukan
Inheritance of Glory
Device Transfer Guide
Best Craft Essence: Craft Essence Tier List
FGO Reroll Tier List [5/11 updated!]
Saint Quartz Farming Guide
NP Damage - Craft Essences
How to Complete Master Missions [JP May 7 - May 13]
Demon (Demonic) Servants & Enemies
Black Holy Grail (The Black Grail)