Black Sabbath · Master of Reality · song 4
Children of the Grave tuning.
Children of the Grave (Black Sabbath, 1971) is in C♯ Standard at concert pitch (A 440), measured by TuneLit from the record.

Measured by TuneLit
At concert pitch
The album's value, measured on the CD.
Black Sabbath · Master of Reality · 1971
About Children of the Grave
The galloping heart of Master of Reality (1971), introduced by the short Embryo. Tony Iommi named it as one of the three songs he tuned three semitones down, to C♯ Standard (C♯ F♯ B E G♯ C♯), for a bigger, heavier sound and slacker strings.
TuneLit measured the 1986 Castle CD. The album sits at concert pitch (about 4 ¢ flat, stored as A 440), so Tune gives plain C♯ Standard. This song's own reading is weak, because the dense gallop leaves few steady notes, so it uses the album value; nothing suggests it sits elsewhere.
Two of the most-viewed tabs of this song are in C Standard and E♭ Standard, and an E Standard version is popular too. They are rearrangements in tunings players already have, not the record: Iommi's own account and the main transcription agree on C♯. If you use one of them, the riff will be a semitone or more away from the album. Butler's bass is in C♯ as well, so tune it down the same three semitones.
Tip: Play along with the gallop in C♯ and listen for the low open string under the riff; if it beats, recheck String 6 first.
Step by step
Tune your guitar like the record
- Tap Tune like this: the tuner switches to C♯ Standard, the notes Children of the Grave was recorded in.
- From E Standard: Every string down 3 half steps. No tuner that knows C♯ Standard? Clamp a capo across fret 3, tune to E Standard as usual, then take it off: every string drops to C♯ Standard. Check each string again afterwards, since a capo pulls the strings a little sharp.
- Turn String 6 to String 1 until each shows ✓ in tune. Children of the Grave sits at concert pitch on the record, so the tuner stays at A 440.
- Then play Children of the Grave along with the record: its lowest open note and your String 6 should ring together without a wobble.
Or the other way round
Move the record into your tuning
Rather keep your guitar as it is? Let Play along move Children of the Grave instead. Add your own copy, for example from your CD (it never leaves your device); the link already says the song is in C♯ Standard. Choose E Standard at A 440 and Children of the Grave moves up 3 half steps and 4 cents, at its own speed. Slow it down or loop a few bars to learn it, and save the result as a WAV file.
Questions
What tuning is Children of the Grave in?
C♯ Standard: C♯ F♯ B E G♯ C♯, low to high, at the pitch TuneLit measured on the record.