Multiple independent sources (Yonhap, AllKeyShop, and Reuters via web search) confirm the planned strike, with AllKeyShop specifically mentioning the 18-day duration and the May 21 start date.

Web search results from AllKeyShop and other reports indicate the dispute centers on performance-based bonuses, and the failure to reach an agreement led to the strike planning.

Reports from the National Labor Relations Commission (NLRC) via web search confirm that a mediation proposal was put forward around 10 p.m. on the 20th (following the 19th) and that consensus was reached on all but one issue, implying management's refusal of the final point.

Web search results identify Choi Seung-ho as the union leader and report his demands for the 'transparent institutionalization' of the bonus system, which aligns with the claim of formalizing it beyond a one-year period.

Both a cross-reference from Supplychaindigital and web search results (The Guardian, Dawn.com) explicitly state the union's demand to abolish the bonus cap of 50% of annual salaries.

Web search results (Dawn.com and other reports) explicitly mention the union's demand to allocate 15% of annual operating profit to bonuses.

The Guardian reports that Samsung proposed one-off bonuses for logic chip businesses, and other search results mention Samsung's attempt to compete with SK Hynix's bonus levels to prevent engineer defection.

The Guardian explicitly states that Samsung 'in principle, it does not want to abolish the cap on bonuses at 50% of annual salaries,' confirming the proposal to keep the cap in place.