Ogham

Ogham is a real Medieval Irish script of straight and slanted strokes carved along an edge, used to write Primitive and Old Irish (and occasionally Pictish) roughly from the 4th to 10th centuries CE — most famously surviving as inscriptions carved into the edges of standing stones, usually short memorial texts ("X son of Y") marking graves or territory. It's built from groups of 1 to 5 strokes set against a central stemline, organized into Aicmí (groups) of five letters each — that much is solid, well-documented archaeology and linguistics, as are the letter names themselves (mostly genuinely old Old Irish words, several tree/plant names) and the Bríatharogam ("word-oghams," medieval kennings linking each letter to an image, recorded in later manuscripts centuries after the script's active epigraphic use). What is not ancient: the popular "tree calendar" and full divinatory tree-meanings are almost entirely the work of poet Robert Graves in his 1948 book The White Goddess — a modern literary invention repeated so often in 20th-century Druidry and neopaganism that it's frequently mistaken for genuine antiquity, not something uncovered from any Celtic text. None of that makes Ogham divination illegitimate to practice; it makes it honest to practice with eyes open. The 25 letters sort into five Aicmí: Aicme Beithe, the B-group (beginnings and protection), Aicme hÚatha, the H-group (testing and endurance — obstacles that turn out to have a purpose once you're through them), Aicme Muine, the M-group (inner work and transition — introspection, healing, necessary endings), Aicme Ailme, the A-group of vowels (perspective and transformation — stepping back to see clearly, then changing because of what you saw), and Aicme Forfeda, five later medieval additions for sounds the original 20 letters didn't cover — the least standardized group, and the most clearly a later layer on top of the original script. Traditional casting (itself modern, not ancient) uses small wooden staves or wafers drawn from a bag without looking, the same basic gesture as a rune casting; unlike runes, where some staves are genuinely symmetric and structurally can't be reversed, an Ogham stroke's "reversed" reading in modern divination sets has even less historical grounding than a rune's merkstave — a convenience borrowed from other card- and stave-based systems, not a feature of the ancient script. Glossary: stemline/druim (the central line the strokes are set against, often the actual edge of a standing stone in genuine inscriptions) and Forfeda (the 5 later-added letters, less standardized than the original 20).