Rune Divination Was Invented

Blum did not invent the blank rune. His Book of Runes (1982) says it came with a set made in Redhill, Surrey, that reached him in 1976, already glossed as the path of karma.

Ralph Blum, The Book of Runes (1982), 'The Oracle of the Self'.

The modern practice of drawing runes to answer personal questions, popularised from 1982.

Sources2 sources

Primary source

Tacitus, Germania, 98, ch. 10The earliest Roman account of Germanic lot-casting, with slips marked by unnamed 'certain marks' thrown on a white cloth
eosque notis quibusdam discretos super candidam vestem temere ac fortuito spargunt

The tradition itself

Ralph Blum, The Book of Runes: A Handbook for the Use of an Ancient Oracle: The Viking Runes, 1982, 'The Oracle of the Self'; 'The Blank Rune' (pp. 106–107 of the 1985 Guild edition)That Blum's blank rune came with a set made in Redhill, Surrey, which reached him in 1976, and his reading of it as the Unknowable, Odin's rune, in which nothing is predestined
To the twenty-four futhark Runes had been added a Blank Rune