Dynamic J.League Soccer Poster

Create a dynamic vertical sports poster celebrating {argument name="event name" default="J.League Day"}, in a high-energy Japanese graphic design style. Use a clean off-white canvas with an explosive abstract composition of sharp diagonal speed lines, paint splatters, halftone dots, thin technical drafting lines, and angular geometric shards in Japan-inspired colors: deep cobalt blue, vivid red, black, white, and small yellow accents. Center the scene on one male soccer player in a dark {argument name="team jersey" default="Japan national team style black kit with number 10"}, shown in dramatic black-and-white ink illustration with heavy contrast, messy dark hair, athletic build, and a powerful kicking pose angled forward toward the viewer. His face should be obscured or indistinct, keeping the action anonymous. Place exactly one black-and-white soccer ball in the lower left foreground, slightly enlarged with motion blur and speed trails, as if just kicked. Behind the player, create a huge bold black capital letter {argument name="main letter" default="J"} with a thick white outline and red shadow, overlapping a large red sun disk. Add a blue rectangular field of abstract city-like vertical line details in the upper background. Include exactly four main color accent groups: red circular sun and red paint bursts, blue diagonal bars and shards, black ink splashes and halftone patterns, and yellow thin lines plus small polygon accents. Add small printed date text at the bottom right reading {argument name="date text" default="May 15, 2026"} with a loose handwritten signature beneath reading {argument name="signature" default="Oyagi"}. The overall look should feel fast, bold, modern, poster-ready, and suitable for social media AI art; no extra logos, no readable sponsor names, no additional players, no crowd, no stadium background.