Rock Matching and Sample Rock Book

Build a useful team memory

A rock book records what your team has actually seen from identified stones. Begin with the two stones already assigned to you. You are looking for similar travel and a similar path under comparable conditions.

Coach Bill Tschirhart recommends repeated delivered-shot comparisons with similar speed, line and rotation. Matching gives a degree of reliability, not certainty. Two stones reaching the same depth can still take different routes. [1]

• Identify club, sheet, date, handle colour and stone number.
• Keep direction, turn, path, weight, player, release, rotation and sweeping attached to each observation.
• Use 'carried farther,' 'stopped shorter' or 'bent earlier' before making a permanent label.
• If you say 'faster stone,' mean farther travel under comparable delivered conditions, not faster at every point.

Run a fair comparison

This is an original HouseCall practice routine. A careful comparison of two stones is more useful than hurried labels on all eight. Human deliveries will never be perfectly identical.

Use a familiar stone or provisional pair as your reference. A reference is a comparison point, not a certified good stone. Relative similarities matter more than absolute numbers that can change with conditions. [5]

• Use the same player, direction, turn, brush position, intended weight and sweeping plan where practical.
• Deliver normal shots with a similar release and rotation. Record the path and finish, then safely clear each stopped stone before the next trial. [1]
• Alternate the order, revisit the reference and watch for the path changing during practice.
• Keep off-line deliveries and other exceptions in the record, but mark them unsuitable for direct comparison.
• Three comparable attempts is a practical starting plan, not scientific proof. If results disagree, write 'unclear.'
• Recheck a proposed pair together, then label tests of the other turn, direction and weights separately.

Timing helps only when the context comes with it

Timing is optional. Write the interval name: back-line-to-near-hog measures part of the delivery, while hog-to-hog measures travel between the two hog lines. Agree on the same stone edge and line edge every time. [6]

A split does not prove equal release speed. A hog-to-hog time does not explain the finish by itself. Record the delivery, path and sweeping; allow for manual reaction error. There is no universal split all players should copy.

Sample rock book

FICTIONAL EXAMPLE: All names, stone numbers and observations in this example are invented for teaching. They are not recommended stones or measured performance claims.

Practice A uses red stones on Sheet C, one right-handed thrower, scoreboard-to-windows direction, clockwise draws, the same brush and intended button finish, and no sweeping. Comparable trials show about four rotations from release to stop, an observation for this example rather than a target. No stopwatch is used.

The full printable book contains three passes with each of eight stones, a flagged delivery, candidate pairs, later-game updates and blank records. Visual finishes are rounded to half a stone-width, so 'near target' does not mean an exact measurement.

• Red 1/2 repeatedly finish near the target: a candidate pair for this setup.
• Red 3/4 repeatedly finish a little shorter and farther right: another candidate pair.
• Red 5/6 repeatedly finish a little longer and farther left: a third candidate pair.
• Red 7 repeats reasonably well. Red 8 has one narrow release and two usable but differing results. Their match remains unresolved.
• Sideways finish alone does not measure pure curl when depth also differs. These are observations, not a diagnosis of running-band condition.

Keep the pairing provisional

In the fictional example, the honest result is three candidate pairs and one unresolved comparison. No best skip pair has been established. Test a candidate pair together before relying on it, and keep its tested conditions in the note.

Do not force every stone into a confident label. 'Not enough comparable evidence' is a useful result. The next practice can focus on whether red 8 matches red 7 under better-controlled deliveries.

Add game observations without rewriting history

FICTIONAL CONTINUATION: Red 5 runs deep in the return direction, on the other turn and an outside path with late sweeping. That does not cleanly test it against the earlier unswept practice draws or against red 6.

Later, red 1 and red 2 both carry farther on their familiar practice path. The team records that the pair still appears similar and checks its current path and weight reference. It makes a small adjustment without claiming the cause is proven.

Keep the old record and add the end, conditions, result and next check. Start a fresh dated comparison after reported stone maintenance; World Curling's competition policy provides for informing teams when such work occurs. [7]

Check permissions and leave maintenance to staff

Ask your club or event which stones you may test, select or pair, when changes are allowed and which practice equipment is permitted. Do not assume you can switch stones during a game or borrow from another sheet. World Curling prohibits teams from altering game stones. [4]

The running band matters to stone behaviour, but one finish cannot diagnose a fault. Research on stone surfaces supports taking that interaction seriously, not attempting a repair yourself. [2,3,8]

• Do not scrape, sand, paper, change the running surface or replace handles yourself.
• Report visible damage or a repeated concern to the ice technician or official with your dated observations.
• Keep the notebook brief enough that your team can use it without slowing the game.

Print a small book for your next practice

The downloadable book includes a filled example and three blank reusable pages: a session and path map with an empty house, a comparison trial log, and a pair card with game updates.

Start with one session sheet, one log and one card. You are building useful team memory, not a permanent ranking of the stones.

Take it to practice

Building a team · Reading ice

Download the printable guide for worked examples and reusable worksheets. Clubs may download, print and share it for noncommercial educational use. Keep the credit to Mary Deuhs and HouseCall. Not for resale.

Plan a practice · Sweeping and communication · Learning path