NSK Kogyo Oboro Knife 200

The NSK 200 diamond stone is a great tool with some impressive qualities. Its hardness is unparalleled—super tough without feeling overly glassy—which makes it highly effective for demanding sharpening tasks. The abrasive power is excellent, delivering precise results, especially for repair work, correcting bevel geometry, or setting bevels ahead of a polishing project. That said, it’s not without its downsides. While diamond stones wear significantly less than synthetic ones, they’re not immune to wear and still require maintenance. This is particularly inconvenient for polishing projects, where a perfectly flat surface is critical. To make the most of its capabilities, you’ll likely need additional tools like a hard silicon carbide (SIC) powder or stone paired with a tempered glass plate for flattening and maintenance. Another consideration is the price—it costs as much as four quality synthetic stones or a solid knife. Whether it’s worth the investment depends on your needs and priorities. For professionals or serious enthusiasts who rely on precise and durable sharpening tools, the NSK 200 is a standout option with few true alternatives. However, for hobbyists, it might be overkill unless you’re deeply committed to sharpening as a craft. Overall, I would say that if you’re willing to invest in additional tools (coarse stone) and need this level of precision, it’s a worthy addition to your polishing/sharpening arsenal or at least worth a try (if possible!).