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The 823's flow is famously generous; Tomoe's extreme sizing keeps the river on the surface. A near-textbook match.
Medium on glass — comfortable, perhaps boring. A finer nib would have rated higher on this axis; we deduct points for fairness.
The whole reason the marriage exists. Tomoe pools just enough for any sheening ink to declare its second colour.
The 823 is soft, not flexed; sizing here is overkill for the line-variation modest it allows. Still very high.
Correspondence and journaling, contemplative hours — the temperament of pen and paper align without effort.
| Dry time | 38 seconds | Iroshizuku Tsuki-yo · M nib |
| Bleed-through | None | Verso · clean |
| Ghosting | Visible | Translucent paper — accepted |
| Feathering | Nil | 10× loupe · sharp |
| Show-through | Moderate | Single-sided recommended |
| Sheen observed | Pronounced | Copper · at the troughs |
| Shading | Excellent | Light–to–deep cobalt |
| Line crispness | 9 / 10 | No spread observed |
| Ink | Iroshizuku Tsuki-yo | — |
| Hour | 21:14 | Still |
| Lighting | 2700 K | Desk lamp |
| Temperature | 19 °C | Indoor |
| Humidity | 48 % RH | — |
| Angle | 30° | Sheen-visible |
| Hand | Right · posted · 55° | — |
| Pad of | Sheets 21–24 | Fresh pad |
A wet vacuum-filler finds its translucent altar. The 823's medium 14k lays cobalt in helpings most papers would buckle under; Tomoe River, scarcely fifty-two grams, takes the flood without complaint and returns sheen so pronounced it reads as a different colour at the troughs.
The marriage is famous for a reason: it is, when it works, the easiest demonstration of what fountain pens can do that ballpoints cannot. Reserve for letters one means to be kept, for journals one expects to reread. Allow forty seconds before turning the page.