Every printing process is a mirror, and a woodblock is the plainest possible demonstration of it. Ink is put on the raised surface of a carved plank, a sheet of paper is laid over it, and the back of the sheet is rubbed with a soft brush. Whatever was on the block appears on the paper reversed left to right. To get a page of readable characters, the carver has to cut every one of them backwards. The reversal is not a trick or a convention: it is the geometry of pressing two surfaces together and pulling one away.
The same geometry explains why the picture sits on the raised part. Water-based ink is brushed thinly across the top of the block, so only the highest level gets inked. Everything that should stay white — the field around a figure, the space inside a stroke — is chiselled a few millimetres lower. An intaglio process, where ink sits in cut grooves, needs heavy pressure and a scraper to clear the surface; that suits a press and a thick, hard sheet. A hand-rubbed impression on thin, slightly damp handmade paper asks for the opposite: the ink should be waiting exactly where the paper will touch first.
The paper is damp on purpose. A slightly moist fibre bed takes a thin water-based ink readily and lets it sit on the surface rather than be driven through, and the sheet can be eased into position without springing back. Too dry and the impression comes out patchy; too wet and the ink spreads past the edge of the stroke. The carver, the inker and the printer are working with one material system, not three separate crafts.
Why one plank holds the whole page
A woodblock holds text and illustration in the same surface, so a page with a picture needs no separate arrangement. That is a real advantage over setting individual characters: the drawing can run behind the columns, and a border can be part of the same cut. The cost is that the block is committed. A wrong stroke cannot be lifted out and replaced; it has to be chiselled away and a small plug of the same wood fitted into the recess, grain aligned, then recut. Examined closely, a long-lived block often shows these neat rectangular repairs.
The wood itself is chosen for the cut, not for the printing. Fine, even-grained hardwood — pear, jujube and similar — holds a crisp edge without crumbling, takes a knife along the grain, and absorbs and releases ink evenly. Coarse grain telegraphs itself into every long stroke; a knot can deflect a line at the worst possible moment. Blocks are cut with the grain running along the length of the columns, so the knife travels with the fibre rather than across it. The plank is also kept flat and dried slowly between runs, because a board that cups will print only its high middle.
Colour makes the mirror problem harder. Each colour gets its own block, and every block has to land in exactly the same place on every sheet. Printers use two small marks cut into the edge of each block and a matching pair of notches or folds on the paper: line those up, lower the sheet, and the colours register. A slip of a millimetre shows as a coloured fringe along one side of a figure. This is why multi-colour prints so often look slightly soft at the edges — the tolerance is being managed by hand, not by a machine.
What wears out first
A block can yield a very large number of impressions, but it does not wear evenly. Thin strokes and the sharp corners where a line turns lose their edge first, because they present the least wood to the brush and take the most pressure. The broad flat faces of a filled area go on almost indefinitely. A long run therefore grows subtly lighter in exactly the places that carried the most detail, which is one reason an early impression and a late one from the same plank can look like different hands.
The work also has a rhythm that follows from the material. Ink is brushed on, the sheet is positioned against the marks, the back is rubbed with a padded brush, and the sheet is peeled off in one movement before the ink can grab. There is nothing to clamp and nothing to reset. The same pair of registration marks serves the whole edition, so the printer's attention stays on pressure and moisture rather than on alignment.
Set this beside the writing brush and the inkstone, and the division of labour becomes clear. Those three tools are built to make a single mark, once, under the hand. A block is built to make the same mark thousands of times, and the carver's skill is spent entirely in advance. The loom solves a similar problem from another direction: both store a pattern in a physical object so that the person repeating it does not have to decide it again.
So the reversed characters are only the visible part of the answer. A raised surface, a low-relief clearance, fine even grain, damp paper, and two small marks at the edge of the plank all come from one fact: the page is taken off the block, not drawn on it. Once that is accepted, everything else about the craft is simply doing that one operation well.