English: The timeline develops from left to right along a horizontal line and contains 3 main stages as follows.

Stage 1. First Filing. This stage includes 1 key event as follows.

• Application filed with national or regional patent office. This constitutes the priority date.

Stage 2. The P C T international phase. This stage includes 8 key events as follows.

• P C T filing occurs 12 months after first filing.
• Transmittal of international search report and written opinion occurs 16 months after first filing.
• At around 18 months, Article 19 amendments are optional.
• International publication occurs 18 months after first filing.
• At 22 months after first filing, supplementary international search request is optional.
• At 22 months after first filing, international preliminary examination demand is optional.
• At 28 months after first filing, a supplementary international search report is processed, if requested.

   At 28 months after first filing, an international preliminary report on patentability, Chapter 2, is processed, if requested.

Stage 3. The P C T national phase. This stage includes 4 key events as follows.

• Communication by the International Bureau to national or regional offices.
• Application enters national phase before selected patent of­fices. National or regional search and examination takes place. 3 examples are provided as follows.
• To visualize the process, Country A, Country B, and Country C are shown on parallel , horizontal timelines on the P C T process. Country B is slightly ahead in the process, followed by Country A and then Country C. Each application is subject to grant or refusal by national or regional offices.

A list of the 4 main benefits of the P C T System reads as follows.

• One P C T application with legal effect in all P C T Contracting States.
• Harmonized formal requirements.
• Receive patentability information to support strategic decision-making.
• Postpone signifi­cant costs for national processing by 18 months.