Is there a primary source that explains the original 1–9 bead bar color code and whether Maria intended it to support factor recognition in the decanomial square? Our 9 is dark blue (Nienhuis, 2018) and I lean on that cue when laying out the 9 long chain with tickets, but I’ve never found the documented rationale.
Same here — “I’ve never found the documented rationale.” Montessori’s books describe the chains but don’t fix the 1–9 hues, so 9-as-dark-blue is likely an early AMI/Nienhuis convention; I’d annotate your album with your supplier’s palette and note it as a convention for factor work (the colors feel more like dialect than scripture). Want me to ask the AMI archives if there’s a 1920s catalog plate that spells it out?
I’ve had better luck checking early supplier catalogs than Montessori’s texts; if you can find scans of 1930s Nienhuis or Gonzagarredi pages, you’ll sometimes see “9-as-dark-blue” alongside the decanomial layout. Small caveat: hues drift across printings and glass batches, so factor spotting feels like a teacherly bonus rather than an explicit directive. If you want a concrete lead, reach out to the AMI Archives — they’ve sent catalog pages on request, which beats squinting at dye lots from the 1920s.