Skip to main content
Metrics type: Key Metrics • Category: Shipping & Courier

​
At a glance

Share of Japan Post (Yu-Pack domestic, EMS international, Letter Pack) consignments delivered on or before the published delivery date for the service tier. Japan Post reliability is legendary in domestic delivery (typically 99 percent OTD), making this dial less about underperformance and more about detecting weekend-processing artefacts and the rare network anomaly. International EMS reads materially lower because customs lag in destination countries is included in the OTD measurement.

​
Calculation

Calculated automatically from your Japan Post data. See the At a glance summary above for what the metric tracks and the worked example below for a typical reading.

​
Worked example

A Japanese manga and anime collectibles retailer based in Akihabara, Tokyo. Around 4,500 consignments per week, mix: 65 percent Yu-Pack domestic (the everyday default), 25 percent EMS international (collectors in US, EU, AU, SG), 10 percent Letter Pack Plus (small accessories, badges, posters). Reading taken at 09:00 JST on 12 Mar 26 for the trailing 30 days (10 Feb 26 to 11 Mar 26). Card reads 95.7 percent, comfortably above the 95 warn threshold. Four observations:
  1. The international tail dominates the gap to perfection. Domestic reads 99.2 percent, the international leg drags the aggregate down. If this merchant were domestic-only, the card would read 99.3 percent. The merchant should not aim to “fix” Japan Post; the lever is checkout copy and destination-country expectations for international.
  2. EMS to UK reads structurally lower. Of the 675 missed-aim international consignments, roughly 240 went to UK addresses where post-Brexit customs lag adds 3 to 7 days. EMS to US, AU, SG runs 90+ percent; EMS to UK runs 65 to 75 percent. Pair with Shipments by Destination.
  3. Yu-Pack near-perfection is not surprising. Japan Post’s domestic network is one of the highest-reliability postal operations in the world. A 99.2 percent reading is normal; readings below 98 percent should trigger investigation, not the 95 percent threshold this template inherits.
  4. Letter Pack Plus also at 99.5 percent. Small flat consignments fit the post-box delivery flow, do not require recipient signature, and deliver structurally faster than Yu-Pack on the same lane. For light items it is the cheaper, equally-reliable option.

​
Sibling cards merchants should reference together

​
Reconciling against the vendor’s own dashboard

Where to look in Japan Post’s own portal: Japan Post Business → Web Yu-Pri (My Page) → Reports → Delivery Performance for SME merchants. Larger Yu-Biz contract customers use the Yu-Biz portal → Service Performance Report, which is the source of truth for SLA discussions. Why our number may legitimately differ from Japan Post’s report: Cross-connector reconciliation:

​
Known limitations / merchant FAQs

My OTD reads 95.7 percent. Is that bad for Japan Post? For domestic-only merchants yes; for cross-border merchants no. Domestic Japan Post Yu-Pack baseline is 99 to 99.5 percent. If your business is 100 percent domestic and you read 95.7 percent, something is wrong. If you ship 25 to 35 percent international EMS, 95 to 96 percent is the normal aggregate because EMS reads structurally lower. The merchant takeaway is to look at the domestic and international components separately, not the aggregate. The portal shows 96.4 percent and Vortex IQ shows 95.7 percent. Why? Two common reasons: (1) the portal sometimes pauses the SLA clock during customs holds for international consignments while the card never pauses; (2) JST vs UTC boundary effects on “today” comparisons. On a 30-day rolling reading the gap should be under 1 point. EMS to UK runs 65 to 75 percent for me. What is causing it? Brexit-era customs friction. Since Jan 2021 EMS consignments to UK pass through HMRC customs which adds 3 to 7 calendar days plus a small percentage of stuck-at-customs cases (1 to 3 percent). Japan Post’s published EMS aim to UK is 5 to 7 days; actual is often 8 to 14. The action: tighten checkout copy (“delivery to UK 8 to 14 days due to customs”), or offer EMS Premium (where Japan Post pays UK Royal Mail for last-mile guarantee). My OTD dropped during typhoon season. Will it recover? Yes, within 1 to 2 weeks of the typhoon clearing. Japan Post resumes normal service quickly; the depressed week is the typhoon’s actual transit-time impact, not a structural shift. Annotate the alert as weather-driven and reset thresholds for the affected week. Why does Japan Post weekend processing affect my OTD? Yu-Pack delivers Mon-Sat in metros (most of the time, varies by route) but only Mon-Fri in many rural prefectures. Sunday delivery is a premium-only service. If you ship Friday afternoon to a rural prefecture with a Monday aim, the parcel often arrives Tuesday and counts as late. The published aim sometimes already accounts for this; sometimes not. Use OTD by Route to detect Friday-shipment-to-rural patterns. Should I split EMS-to-UK from EMS-to-US in my reading? Yes, those are functionally different services. EMS to US averages 4 to 6 days end-to-end with 90+ percent OTD; EMS to UK averages 8 to 14 days with 65 to 75 percent OTD; EMS to AU averages 5 to 8 days with 88 to 92 percent OTD. Use OTD by Route for per-destination splits and price/expectation differently in checkout. My alert just fired at 92 percent. What is the playbook? (1) Check Japan Post’s service updates for typhoon, earthquake, or fire/disaster notifications affecting prefectures. (2) Check whether your international mix shifted, EMS share moving from 25 percent to 35 percent typically drags the aggregate 2 to 3 points. (3) Check Exception Rate for upstream label-data issues like address-formatting on rōmaji-only addresses. (4) Check OTD by Route for prefecture concentration. (5) If domestic Yu-Pack dropped below 98 percent it is a real network event; contact your Yu-Biz account manager. How do I plan for Oseibo and Ochugen peak? Mid-December (Oseibo / year-end gift season) and mid-July (Ochugen / mid-summer gift season) drive 2 to 3x normal volume. Domestic OTD typically holds within 1 to 2 points; international EMS compresses 3 to 6 points. Three actions: (1) ship outbound 2 to 3 days earlier than normal aim; (2) for international, pre-warn customers in destination countries that customs is also under peak load; (3) avoid heavy Yu-Pack Cool (chilled) bookings during typhoon season since the chilled-network has tighter capacity. Letter Pack Plus vs Yu-Pack, which should I use? Letter Pack Plus is a flat-rate prepaid envelope service (JPY 520 fixed price domestic), excellent for items under 4kg that fit the envelope. Same delivery speed as Yu-Pack on most lanes, half the cost, no recipient signature required (parcel goes to the post-box). Manga, posters, badges, small accessories ship Letter Pack Plus. Anything bulky, fragile, or over 4kg is Yu-Pack. International Letter Pack does not exist; international goes EMS or untracked Surface Mail.

​
Tracked live in Vortex IQ Nerve Centre

On-Time Delivery Rate is one of hundreds of KPI pulses Vortex IQ tracks across Japan Post and 70+ other ecommerce connectors. Nerve Centre runs the detection layer; Vortex Mind investigates the cause when something moves; Ask Viq lets you interrogate any number in plain English. Start for free or book a demo to see this metric running on your own data.