Methodology & Data Sources

Data Source

JSDA (Japan Securities Dealers Association) OTC bond reference prices.

TDB: Treasury Discount Bills. Tenors: 1M / 3M / 6M.
JGB: Japanese Government Bonds (coupon-bearing). Tenors: 1Y / 2Y / 3Y / 5Y / 7Y / 10Y / 15Y / 20Y / 25Y / 30Y / 35Y / 40Y.

Update frequency: daily (business days). Not updated on weekends/holidays.

Yield Display

"Standard" view: TDB as simple interest, JGB as compound interest (YTM). "Compound only" / "Simple only" let you view either basis separately.

Compound-basis yields use JSDA's published values as-is (no independent recalculation).

Calculation Method by Tenor

The yield for each tenor is calculated using one of the methods below. The method used for each date/tenor is shown in the data table.

exact: The quoted price of a security exactly matching that tenor.
linear_interpolation: Linear interpolation between the two surrounding observed points.
linear_extrapolation_nearest_two: Estimated by extending the slope of the nearest two points beyond the observed range.
linear_regression_25Y_35Y: Estimated from a regression line fitted to multiple points between 25Y and 35Y. Mainly used for 40Y.

Each row also includes the number of securities used in the calculation (source_points). Short-term (TDB) typically comprises 20-30 securities, long-term (JGB) typically 100-160.

Chart Display Specification

X-axis: Tenors are shown at equal intervals (category axis), not proportional to actual years to maturity.
Y-axis: Yield (%). Linear scale.
Multiple dates: Up to 10 dates can be overlaid on the same chart.
Image export: The "Save as image" button exports a PNG (white background).

Shortcut Reference Dates

Latest: The most recent date for which data exists.
Prev. business day: Going back one calendar day at a time from the latest date, the first date that is not a Saturday or Sunday.
1 month ago / 1 year ago: Calendar month/year offset from the latest date. If no data exists for that exact date, it automatically falls back to the most recent prior date.