held
what it holds
Held holds the number of fast blocks elapsed since the slow clock was last seen to move. The endpoint is an observation rather than an event, so the count begins where a mark found the movement, not where the movement occurred.
It is computed from the current block rather than stored.1 The record keeps the fast block of the last observed movement and subtracts it from the block being read now.
That makes it the only value on this site that changes without anyone touching the contract. Every other figure waits for a caller.
It is also the only value that can fall. When the slow clock is next seen to move, held returns to zero and starts again.
what writes it
Strictly nothing writes held. What is written is the anchor, and a mark updates the anchor whenever it finds the slow clock at a value different from the one stored.
Between anchor updates the field rises by one for every fast block the chain produces, without any transaction and without any cost to anyone.1
A reader who calls the contract twice will see two different values with no instruction in between. This is expected, and it is the reason the value is presented as a reading rather than as a total.
When a mark moves the anchor, the span that had accumulated is settled into witnessed or dark according to what the mark could prove.
what it cannot do
Held is not a stall length until a mark closes it. Until then it is a running count that may end at the very next block or may keep going.
It cannot contribute to any total. Nothing in witnessed, dark or deepest comes from the field itself, only from the closed interval it becomes.
It cannot be preserved. Nothing records the high water mark of held for a stall that nobody closed, and such a value leaves no trace anywhere.
It cannot be trusted as a start point either, because the anchor behind it is the last observed movement rather than the last actual one.
how to read it
A high held is not a failure of the record. It is the condition the record exists to notice, and the field rising is the record working rather than the record breaking.
Read it against the nominal ratio. A held far above the ratio implied by the two nominal block times means the settlement clock is behind its usual cadence.1
Read it against the quiet window. A held approaching that window means a lapse will shortly be callable if no mark lands.
The table lists past runs of held with their final values, which is the only place the field's history survives.
| opened at | closed at | final value | what closed it |
|---|---|---|---|