A Kagi chart is a Japanese charting technique that displays price movements using vertical lines of varying thickness. Unlike time-based charts, Kagi charts change direction only when price moves by a significant amount (the reversal threshold), effectively filtering out market noise. Thick lines (yang) indicate uptrends when price exceeds previous highs, while thin lines (yin) show downtrends when price falls below previous lows, making trend identification intuitive.
""" anyplot.ai
kagi-basic: Basic Kagi Chart
Library: bokeh 3.9.0 | Python 3.13.13
Quality: 90/100 | Updated: 2026-05-17
"""
import os
import sys
import time
from pathlib import Path
# Remove script directory from sys.path to avoid shadowing bokeh package
script_dir = os.path.dirname(os.path.abspath(__file__))
while script_dir in sys.path:
sys.path.remove(script_dir)
if "" in sys.path:
sys.path.remove("")
if "." in sys.path:
sys.path.remove(".")
import numpy as np
from bokeh.io import output_file, save
from bokeh.models import ColumnDataSource, Legend, LegendItem
from bokeh.plotting import figure
from selenium import webdriver
from selenium.webdriver.chrome.options import Options
# Theme tokens
THEME = os.getenv("ANYPLOT_THEME", "light")
PAGE_BG = "#FAF8F1" if THEME == "light" else "#1A1A17"
ELEVATED_BG = "#FFFDF6" if THEME == "light" else "#242420"
INK = "#1A1A17" if THEME == "light" else "#F0EFE8"
INK_SOFT = "#4A4A44" if THEME == "light" else "#B8B7B0"
# Okabe-Ito palette
YANG_COLOR = "#009E73" # First series - bluish green
YIN_COLOR = "#AE3030" # imprint red — bearish
# Data generation
np.random.seed(42)
n_days = 250
# Simulate a stock price with trends
base_price = 100.0
returns = np.random.normal(0.001, 0.02, n_days)
# Add some trending periods
returns[20:60] += 0.003 # Uptrend
returns[80:120] -= 0.004 # Downtrend
returns[150:200] += 0.002 # Uptrend
prices = base_price * np.cumprod(1 + returns)
# Kagi chart algorithm
reversal_pct = 0.04 # 4% reversal threshold
current_price = prices[0]
direction = 1 # 1 for up, -1 for down
is_yang = True # Start as yang (thick)
line_index = 0
last_high = prices[0]
last_low = prices[0]
# Store kagi line segments: (x1, y1, x2, y2, is_yang)
segments = []
for i in range(1, len(prices)):
price = prices[i]
reversal_amount = current_price * reversal_pct
if direction == 1: # Currently going up
if price > current_price:
# Continue upward - extend vertical line
if price > last_high:
is_yang = True # Becomes yang when exceeds previous high
last_high = max(last_high, price)
segments.append((line_index, current_price, line_index, price, is_yang))
current_price = price
elif current_price - price >= reversal_amount:
# Reversal down - draw horizontal shoulder
segments.append((line_index, current_price, line_index + 1, current_price, is_yang))
line_index += 1
direction = -1
if price < last_low:
is_yang = False # Becomes yin when falls below previous low
last_low = min(last_low, price)
segments.append((line_index, current_price, line_index, price, is_yang))
current_price = price
else: # Currently going down
if price < current_price:
# Continue downward - extend vertical line
if price < last_low:
is_yang = False # Becomes yin when falls below previous low
last_low = min(last_low, price)
segments.append((line_index, current_price, line_index, price, is_yang))
current_price = price
elif price - current_price >= reversal_amount:
# Reversal up - draw horizontal waist
segments.append((line_index, current_price, line_index + 1, current_price, is_yang))
line_index += 1
direction = 1
if price > last_high:
is_yang = True # Becomes yang when exceeds previous high
last_high = max(last_high, price)
segments.append((line_index, current_price, line_index, price, is_yang))
current_price = price
# Prepare data for ColumnDataSource - separate yang and yin
xs_yang, ys_yang = [], []
xs_yin, ys_yin = [], []
for seg in segments:
x1, y1, x2, y2, yang = seg
if yang:
xs_yang.append([x1, x2])
ys_yang.append([y1, y2])
else:
xs_yin.append([x1, x2])
ys_yin.append([y1, y2])
source_yang = ColumnDataSource(data={"xs": xs_yang, "ys": ys_yang})
source_yin = ColumnDataSource(data={"xs": xs_yin, "ys": ys_yin})
# Create figure
p = figure(
width=4800,
height=2700,
title="kagi-basic · bokeh · anyplot.ai",
x_axis_label="Line Index",
y_axis_label="Price ($)",
)
# Plot kagi lines - yang (thick) and yin (thin) with ColumnDataSource
yang_renderer = p.multi_line(xs="xs", ys="ys", source=source_yang, line_color=YANG_COLOR, line_width=8)
yin_renderer = p.multi_line(xs="xs", ys="ys", source=source_yin, line_color=YIN_COLOR, line_width=3)
# Styling - scaled for 4800x2700 canvas
p.title.text_font_size = "28pt"
p.title.text_color = INK
p.xaxis.axis_label_text_font_size = "22pt"
p.yaxis.axis_label_text_font_size = "22pt"
p.xaxis.axis_label_text_color = INK
p.yaxis.axis_label_text_color = INK
p.xaxis.major_label_text_font_size = "18pt"
p.yaxis.major_label_text_font_size = "18pt"
p.xaxis.major_label_text_color = INK_SOFT
p.yaxis.major_label_text_color = INK_SOFT
p.xaxis.axis_line_color = INK_SOFT
p.yaxis.axis_line_color = INK_SOFT
p.xaxis.major_tick_line_color = INK_SOFT
p.yaxis.major_tick_line_color = INK_SOFT
# Grid styling - subtle, solid lines
p.xgrid.grid_line_color = INK
p.ygrid.grid_line_color = INK
p.xgrid.grid_line_alpha = 0.10
p.ygrid.grid_line_alpha = 0.10
# Background
p.background_fill_color = PAGE_BG
p.border_fill_color = PAGE_BG
p.outline_line_color = INK_SOFT
# Add legend with larger, more prominent text
legend = Legend(
items=[
LegendItem(label="Yang (Uptrend)", renderers=[yang_renderer]),
LegendItem(label="Yin (Downtrend)", renderers=[yin_renderer]),
],
location="top_left",
label_text_font_size="20pt",
)
p.add_layout(legend)
p.legend.background_fill_color = ELEVATED_BG
p.legend.background_fill_alpha = 0.9
p.legend.border_line_color = INK_SOFT
p.legend.label_text_color = INK_SOFT
# Save HTML
output_file(f"plot-{THEME}.html")
save(p)
# Screenshot with headless Chrome via Selenium
W, H = 4800, 2700
opts = Options()
for arg in (
"--headless=new",
"--no-sandbox",
"--disable-dev-shm-usage",
"--disable-gpu",
f"--window-size={W},{H}",
"--hide-scrollbars",
):
opts.add_argument(arg)
driver = webdriver.Chrome(options=opts)
driver.set_window_size(W, H)
driver.get(f"file://{Path(f'plot-{THEME}.html').resolve()}")
time.sleep(3) # Let Bokeh's JS render
driver.save_screenshot(f"plot-{THEME}.png")
driver.quit()
Part of Basic Kagi Chart on anyplot.ai.