Tonbo Brief archive

Midweek dispatches

Wednesday observations on the JDM watch market. The shorter companion to the Sunday Snowflake newsletter.

Brief #06

Tonbo Brief . 6-10 . 62MAS pricing looks broken

Wednesday, June 10, 2026

Two 62MAS listings. One question. The Seiko 6217-8000 is the original First Diver. Made between 1965 and 1968. It's the watch the 62MAS collectors argue about, the one that commands serious money when it shows up in...

Brief #05

Tonbo Brief · 6-3 · When the data misfires

Wednesday, June 03, 2026

The listing that looks like a steal. And isn't Three deals topped this week's margin scan. Two of them are the same seller, same product category, posted twice with slightly different SKUs. The third has a 89% margin...

Brief #03

Tonbo Brief · 5-27 · Grand Seiko straps hiding in plain sight

Tuesday, May 26, 2026

The accessory arbitrage nobody talks about Most flippers chase the watch. The strap is an afterthought. But this week's data surfaced something worth paying attention to: genuine Grand Seiko leather straps, new old...

Brief #02

Tonbo Brief · 5-20 · Vintage Lord Matic spreads

Wednesday, May 20, 2026

The mid-tier vintage floor just moved Three Lord Matics closed this week with gross spreads above $85. All under $115 landed. That's the kind of margin you used to see only on mint SARB pieces or popular Alpinists....

Brief #01

Tonbo Brief · 5-13 · The 6309 margin puzzle

Wednesday, May 13, 2026

The vintage diver nobody's watching You know the Seiko 6309. Mid-70s to mid-80s diver. Came before the 7S26 generation. Usually listed between ¥15,000 and ¥35,000 depending on condition. Solid tool watch. Nothing...